Paul McIntyre
Rick and Melinda Reed Professor, Professor of Photon Science and Senior Fellow at the Precourt Institute for Energy
Materials Science and Engineering
Bio
McIntyre's group performs research on nanostructured inorganic materials for applications in electronics, energy technologies and sensors. He is best known for his work on metal oxide/semiconductor interfaces, ultrathin dielectrics, defects in complex metal oxide thin films, and nanostructured Si-Ge single crystals. His research team synthesizes materials, characterizes their structures and compositions with a variety of advanced microscopies and spectroscopies, studies the passivation of their interfaces, and measures functional properties of devices.
Academic Appointments
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Professor, Materials Science and Engineering
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Professor, Photon Science Directorate
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Member, Bio-X
Administrative Appointments
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Associate Lab Director, SLAC National Accelerator Laboratory (2019 - Present)
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Director, Stanford Synchrotron Radiation LIghtsource (2019 - Present)
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Department Chair, Materials Science and Engineering (2014 - 2019)
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Director, Geballe Laboratory for Advance Materials (2008 - 2013)
Boards, Advisory Committees, Professional Organizations
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Member, Board of Directors, Materials Research Society (2018 - 2020)
Program Affiliations
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Stanford SystemX Alliance
Professional Education
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ScD, MIT (1993)
2024-25 Courses
- Rate Processes in Materials
MATSCI 182 (Win) - Rate Processes in Materials
MATSCI 212 (Win) -
Independent Studies (7)
- Graduate Independent Study
MATSCI 399 (Aut, Win, Spr) - Master's Research
MATSCI 200 (Aut, Win, Spr) - Participation in Materials Science Teaching
MATSCI 400 (Aut, Win, Spr) - Ph.D. Research
MATSCI 300 (Aut, Win, Spr) - Practical Training
MATSCI 299 (Aut, Win, Spr) - Undergraduate Independent Study
MATSCI 100 (Aut, Win, Spr) - Undergraduate Research
MATSCI 150 (Aut, Win, Spr)
- Graduate Independent Study
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Prior Year Courses
2023-24 Courses
- Rate Processes in Materials
MATSCI 182 (Win) - Rate Processes in Materials
MATSCI 212 (Win)
2022-23 Courses
- Rate Processes in Materials
MATSCI 182 (Win) - Rate Processes in Materials
MATSCI 212 (Win)
2021-22 Courses
- Rate Processes in Materials
MATSCI 182 (Win) - Rate Processes in Materials
MATSCI 212 (Win)
- Rate Processes in Materials
Stanford Advisees
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Doctoral Dissertation Reader (AC)
Jarod Meyer, Akash Ramdas, Riley Zhang -
Postdoctoral Faculty Sponsor
Anis Attiaoui, Didem Dede -
Doctoral Dissertation Advisor (AC)
Karina Masalkovaite, Cristian Ruano Arens, Balreen Saini -
Master's Program Advisor
Chia Lee -
Postdoctoral Research Mentor
Anis Attiaoui -
Doctoral (Program)
Balreen Saini
All Publications
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Dimensional Scaling of Ferroelectric Properties of Hafnia-Zirconia Thin Films: Electrode Interface Effects.
ACS nano
2024
Abstract
Hafnia-based ferroelectric (FE) thin films are promising candidates for semiconductor memories. However, a fundamental challenge that persists is the lack of understanding regarding dimensional scaling, including thickness scaling and area scaling, of the functional properties and their heterogeneity in these films. In this work, excellent ferroelectricity and switching endurance are demonstrated in 4 nm-thick Hf0.5Zr0.5O2 (HZO) capacitors with molybdenum electrodes in capacitors as small as 65 nm × 45 nm in size. The HZO layer in these capacitors can be crystallized into the ferroelectric orthorhombic phase at the low temperature of 400 °C, making them compatible for back-end-of-line (BEOL) FE memories. With the benefits of thickness scaling, low operation voltage (1.2 V) is achieved with high endurance (>1010 cycles); however, a significant fatigue regime is noted. We observed that the bottom electrode, rather than the top electrode, plays a dominant role in the thickness scaling of HZO ferroelectric behavior. Furthermore, ultrahigh switched polarization (remanent polarization 2Pr ∼ 108 μC cm-2) is observed in some nanoscale devices. This study advances the understanding of dimensional scaling effects in HZO capacitors for high-performance FE memories.
View details for DOI 10.1021/acsnano.4c01992
View details for PubMedID 38916257
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Atomic Layer Deposition of WO3-Doped In2O3 for Reliable and Scalable BEOL-Compatible Transistors.
Nano letters
2024
Abstract
Tungsten oxide (WO3) doped indium oxide (IWO) field-effect transistors (FET), synthesized using atomic layer deposition (ALD) for three-dimensional integration and back-end-of-line (BEOL) compatibility, are demonstrated. Low-concentration (1∼4 W atom %) WO3-doping in In2O3 films is achieved by adjusting cycle ratios of the indium and tungsten precursors with the oxidant coreactant. Such doping suppresses oxygen deficiency from In2O2.5 to In2O3 stoichiometry with only 1 atom % W, allowing devices to turn off stably and enhancing threshold voltage stability. The ALD IWO FETs exhibit superior performance, including a low subthreshold slope of 67 mV/decade and negligible hysteresis. Strong tunability of the threshold voltage (Vth) is achieved through W concentration tuning, with 2 atom % IWO FETs showing an optimized Vth for enhancement-mode and a high drain current. ALD IWO FETs have remarkable stability under bias stress and nearly ideal performance extending to sub-100 nm channel lengths, making them promising candidates for high-performance monolithic 3D integrated devices.
View details for DOI 10.1021/acs.nanolett.4c00746
View details for PubMedID 38686670
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Enhanced Switching Reliability of Hf0.5Zr0.5O2 Ferroelectric Films Induced by Interface Engineering.
ACS applied materials & interfaces
2023
Abstract
Ferroelectric materials have been widely researched for applications in memory and energy storage. Among these materials and benefiting from their excellent chemical compatibility with complementary metal-oxide-semiconductor (CMOS) devices, hafnia-based ferroelectric thin films hold great promise for highly scaled semiconductor memories, including nonvolatile ferroelectric capacitors and transistors. However, variation in the switched polarization of this material during field cycling and a limited understanding of the responsible mechanisms have impeded their implementation in technology. Here, we show that ferroelectric Hf0.5Zr0.5O2 (HZO) capacitors that are nearly free of polarization "wake-up"─a gradual increase in switched polarization as a function of the number of switching cycles─can be achieved by introducing ultrathin HfO2 buffer layers at the HZO/electrodes interface. High-resolution transmission electron microscopy (HRTEM) reveals crystallite sizes substantially greater than the film thickness for the buffer layer capacitors, indicating that the presence of the buffer layers influences the crystallization of the film (e.g., a lower ratio of nucleation rate to growth rate) during postdeposition annealing. This evidently promotes the formation of a polar orthorhombic (O) phase in the as-fabricated buffer layer samples. Synchrotron X-ray diffraction (XRD) reveals the conversion of the nonpolar tetragonal (T) phase to the polar orthorhombic (O) phase during electric field cycling in the control (no buffer) devices, consistent with the polarization wake-up observed for these capacitors. The extent of T-O transformation in the nonbuffer samples is directly dependent on the duration over which the field is applied. These results provide insight into the role of the HZO/electrodes interface in the performance of hafnia-based ferroelectrics and the mechanisms driving the polarization wake-up effect.
View details for DOI 10.1021/acsami.3c08895
View details for PubMedID 37856882
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Kinetics and mechanism of light-induced phase separation in a mixed-halide perovskite
MATTER
2023; 6 (6): 2052-2065
View details for DOI 10.1016/j.matt.2023.04.025
View details for Web of Science ID 001043983600001
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Atomic-Layer-Deposited TiO2-IrO X Nanoscale Thin-Film Electrocatalysts for Water and Chloride Oxidation: Influence of Local Phase Separation
ACS APPLIED ENERGY MATERIALS
2023
View details for DOI 10.1021/acsaem.3c00216
View details for Web of Science ID 001008133200001
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Field-Induced Ferroelectric Phase Evolution During Polarization "Wake-Up" in Hf0.5Zr0.5O2 Thin Film Capacitors
ADVANCED ELECTRONIC MATERIALS
2023
View details for DOI 10.1002/aelm.202300016
View details for Web of Science ID 000972337100001
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Local ordering in Ge/Ge-Sn semiconductor alloy core/shell nanowires revealed by extended x-ray absorption fine structure (EXAFS)
APPLIED PHYSICS LETTERS
2023; 122 (6)
View details for DOI 10.1063/5.0136746
View details for Web of Science ID 000932386200011
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Nanocrystallite Seeding of Metastable Ferroelectric Phase Formation in Atomic Layer-Deposited Hafnia-Zirconia Alloys.
ACS applied materials & interfaces
2022
Abstract
Hafnia-based ferroelectric thin films are promising for semiconductor memory and neuromorphic computing applications. Amorphous, as-deposited, thin-film binary alloys of HfO2 and ZrO2 transform to the metastable, orthorhombic ferroelectric phase during post-deposition annealing and cooling. This transformation is generally thought to involve formation of a tetragonal precursor phase that distorts into the orthorhombic phase during cooling. In this work, we systematically study the effects of atomic layer deposition (ALD) temperature on the ferroelectricity of post-deposition-annealed Hf0.5Zr0.5O2 (HZO) thin films. Seed crystallites having interplanar spacings consistent with the polar orthorhombic phase are observed by a plan-view transmission electron microscope in HZO thin films deposited at an elevated ALD temperature. After ALD under conditions that promote formation of these nanocrystallites, high-polarization (Pr > 18 muC/cm2) ferroelectric switching is observed after rapid thermal annealing (RTA) at low temperature (350 °C). These results indicate the presence of minimal non-ferroelectric phases retained in the films after RTA when the ALD process forms nanocrystalline particles that seed subsequent formation of the polar orthorhombic phase.
View details for DOI 10.1021/acsami.2c15047
View details for PubMedID 36384298
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Oxide Decomposition and Sn Surface Segregation on Core/Shell Ge/ GeSn Nanowires
ACS APPLIED ELECTRONIC MATERIALS
2022
View details for DOI 10.1021/acsaelm.2c01061
View details for Web of Science ID 000879875100001
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The 2022 solar fuels roadmap
JOURNAL OF PHYSICS D-APPLIED PHYSICS
2022; 55 (32)
View details for DOI 10.1088/1361-6463/ac6f97
View details for Web of Science ID 000814374800001
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CeO2 Doping of Hf0.5Zr0.5O2 Thin Films for High Endurance Ferroelectric Memories
ADVANCED ELECTRONIC MATERIALS
2022
View details for DOI 10.1002/aelm.202101258
View details for Web of Science ID 000770370800001
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Measurement of Ferroelectric Properties of Nanometer Scaled Individual Metal/Hf0.5Zr0.5O2/Metal Capacitors
IEEE ELECTRON DEVICE LETTERS
2022; 43 (2): 212-215
View details for DOI 10.1109/LED.2021.3136309
View details for Web of Science ID 000748371400015
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Bending and precipitate formation mechanisms in epitaxial Ge-core/GeSn-shell nanowires.
Nanoscale
2021
Abstract
Core-shell Ge/GeSn nanowires provide a route to dislocation-free single crystal germanium-tin alloys with desirable light emission properties because the Ge core acts as an elastically compliant substrate during misfitting GeSn shell growth. However, the uniformity of tin incorporation during reduced pressure chemical vapor deposition may be limited by the kinetics of mass transfer to the shell during GeSn growth. The balance between Sn precursor flux and available surfaces for GeSn nucleation and growth determines whether defects are formed and their type. On the one hand, when the Sn precursor delivery is insufficient, local variations in Sn arrival rate at the nanowire surfaces during GeSn growth produce asymmetries in shell growth that induce wire bending. This inhomogeneous elastic dilatation due to the varying composition occurs via deposition of Sn-poor regions on some of the {112} sidewall facets of the nanowires. On the other hand, when the available nanowire surface area is insufficient to accommodate the arriving Sn precursor flux, Sn-rich precipitate formation results. Between these two extremes, there exists a regime of growth conditions and nanowire densities that permits defect-free GeSn shell growth.
View details for DOI 10.1039/d1nr04220c
View details for PubMedID 34652350
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Link between Gas Phase Reaction Chemistry and the Electronic Conductivity of Atomic Layer Deposited Titanium Oxide Thin Films.
The journal of physical chemistry letters
2021: 3625–32
Abstract
In situ monitoring of gas phase composition reveals the link between the changing gas phase chemistry during atomic layer deposition (ALD) half-cycle reactions and the electronic conductivity of ALD-TiO2 thin films. Dimethylamine ((CH3)2NH, DMA) is probed as the main product of both the TDMAT and water vapor half-reactions during the TDMAT/H2O ALD process. In-plane electronic transport characterization of the ALD grown films demonstrates that the presence of DMA, a reducing agent, in the ALD chamber throughout each half-cycle is correlated with both an increase in the films' electronic conductivity, and observation of titanium in the 3+ oxidation state by ex situ X-ray photoelectron spectroscopy analysis of the films. DMA annealing of as-grown TiO2 films in the ALD chamber produces a similar effect on their electronic characteristics, indicating the importance of DMA-induced oxygen deficiency of ALD-TiO2 in dictating the electronic conductivity of as-grown films.
View details for DOI 10.1021/acs.jpclett.1c00115
View details for PubMedID 33825465
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Growth mode control for direct-gap core/shell Ge/GeSn nanowire light emission
MATERIALS TODAY
2020; 40: 101–13
View details for DOI 10.1016/j.mattod.2020.05.019
View details for Web of Science ID 000596583700010
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Interfacing Low-Temperature Atomic Layer Deposited TiO2 Electron Transport Layers with Metal Electrodes
ADVANCED MATERIALS INTERFACES
2020; 7 (8)
View details for DOI 10.1002/admi.201902054
View details for Web of Science ID 000529213900024
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Practical challenges in the development of photoelectrochemical solar fuels production
SUSTAINABLE ENERGY & FUELS
2020; 4 (3): 985–95
View details for DOI 10.1039/c9se00869a
View details for Web of Science ID 000518690900002
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Mid-infrared emission and absorption from GeSn/Ge core-shell nanowires with nanophotonic light extraction
IEEE. 2020
View details for Web of Science ID 000612090002472
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Initial growth analysis of ALD Al2O3 film on hydrogen-terminated Si substrate via in situ XPS
JAPANESE JOURNAL OF APPLIED PHYSICS
2020; 59 (1)
View details for DOI 10.7567/1347-4065/ab6273
View details for Web of Science ID 000518978300001
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In-Situ Reflectometry to Monitor Locally-Catalyzed Initiation and Growth of Nanowire Assemblies.
Nanotechnology
2020
Abstract
We investigate in-situ laser reflectometry for measuring the axial growth rate in chemical vapor deposition of assemblies of well-aligned vertical germanium nanowires grown epitaxially on single crystal substrates. Finite Difference Frequency Domain optical simulations were performed in order to facilitate quantitative analysis and interpretation of the measured reflectivity data. The results show an insensitivity of reflected intensity oscillation period to nanowire diameter and density within the range of experimental conditions investigated. Compared to previous quantitative in-situ measurements performed on III-V nanowire arrays, which showed two distinct rate regimes, we observe a constant, steady-state wire growth rate. Furthermore, we show that the measured reflectivity decay can be used to determine the germanium nanowire nucleation time with good precision. This technique provides an avenue to monitor growth of nanowires in a variety of materials systems and growth conditions.
View details for DOI 10.1088/1361-6528/ab8def
View details for PubMedID 32344388
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Imaging light-induced phase separation dynamics of inorganic halide perovskites
IEEE. 2020
View details for Web of Science ID 000612090002152
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Effect of IrO2 Spatial Distribution on the Stability and Charge Distribution of Ti1-xIrxO2 Alloys
CHEMISTRY OF MATERIALS
2019; 31 (21): 8742–51
View details for DOI 10.1021/acs.chemmater.9b02507
View details for Web of Science ID 000497262500016
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Phase-field investigation of the stages in radial growth of core-shell Ge/Ge1-xSnx nanowires.
Nanoscale
2019
Abstract
Core-shell Ge/Ge1-xSnx nanowires are considered promising silicon-compatible nanomaterials with the potential to achieve a direct band-gap for optoelectronic applications. In this study, we systematically investigated the formation of this heterostructure in the radial direction by the phase field method coupled with elasticity. Our model simulated the shell growth of the wire, capturing the evolution of both the sidewall morphology and the strain distribution. We predicted the minimum chemical potential driving forces required for initiating the Ge1-xSnx shell growth at given tin concentrations. In addition, we studied the dependences of the shell growth rate on the chemical potential, the tin concentration, the sidewall interface kinetics and the mass transport rate respectively. From these analyses, we identified three sequential stages of the growth: the Stage 1 growth at an accelerated rate, the Stage 2 growth at a constant rate, and finally the Stage 3 growth at a reduced rate scaling with . This research improves our current understanding on the growth mechanisms of heterogeneous core-shell nanowires, and provides useful guidelines for optimizing nanowire synthesis pathways.
View details for DOI 10.1039/c9nr07587a
View details for PubMedID 31709446
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Reversible Decay of Oxygen Evolution Activity of Iridium Catalysts
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2019; 166 (14): H712–H717
View details for DOI 10.1149/2.0491914jes
View details for Web of Science ID 000489318000001
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Plasmons and inter-band transitions of hexagonal close packed gold nanoparticles
APPLIED PHYSICS LETTERS
2019; 115 (5)
View details for DOI 10.1063/1.5100991
View details for Web of Science ID 000478913700013
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> 10% solar-to-hydrogen efficiency unassisted water splitting on ALD-protected silicon heterojunction solar cells
SUSTAINABLE ENERGY & FUELS
2019; 3 (6): 1490–1500
View details for DOI 10.1039/c9se00110g
View details for Web of Science ID 000469258600011
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Al2O3/Si0.7Ge0.3(001) & HfO2/Si(0.7)Ge0.3(001) interface trap state reduction via in-situ N-2/H-2 RF downstream plasma passivation
APPLIED SURFACE SCIENCE
2019; 478: 1065–73
View details for DOI 10.1016/j.apsusc.2019.01.216
View details for Web of Science ID 000461150400123
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Engineering High-k/SiGe Interface with ALD Oxide for Selective GeOx Reduction
ACS APPLIED MATERIALS & INTERFACES
2019; 11 (16): 15111–21
View details for DOI 10.1021/acsami.8b22362
View details for Web of Science ID 000466052800065
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Engineering High- k/SiGe Interface with ALD Oxide for Selective GeO x Reduction.
ACS applied materials & interfaces
2019
Abstract
Suppression of electronic defects induced by GeO x at the high- k gate oxide/SiGe interface is critical for implementation of high-mobility SiGe channels in complementary metal-oxide-semiconductor (CMOS) technology. Theoretical and experimental studies have shown that a low defect density interface can be formed with an SiO x-rich interlayer on SiGe. Experimental studies in the literature indicate a better interface formation with Al2O3 in contrast to HfO2 on SiGe; however, the mechanism behind this is not well understood. In this study, the mechanism of forming a low defect density interface between Al2O3/SiGe is investigated using atomic layer deposited (ALD) Al2O3 insertion into or on top of ALD HfO2 gate oxides. To elucidate the mechanism, correlations are made between the defect density determined by impedance measurements and the chemical and physical structures of the interface determined by high-resolution scanning transmission electron microscopy and electron energy loss spectroscopy. The compositional analysis reveals an SiO x rich interlayer for both Al2O3/SiGe and HfO2/SiGe interfaces with the insertion of Al2O3 into or on top of the HfO2 oxide. The data is consistent with the Al2O3 insertion inducing decomposition of the GeO x from the interface to form an electrically passive, SiO x rich interface on SiGe. This mechanism shows that nanolaminate gate oxide chemistry cannot be interpreted as resulting from a simple layer-by-layer ideal ALD process, because the precursor or its reaction products can diffuse through the oxide during growth and react at the semiconductor interface. This result shows that in scaled CMOS, remote oxide ALD (oxide ALD on top of the gate oxide) can be used to suppress electronic defects at gate oxide semiconductor interfaces by oxygen scavenging.
View details for PubMedID 30938163
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Atomic Layer Deposited TiO2-IrOx Alloys Enable Corrosion Resistant Water Oxidation on Silicon at High Photovoltage
CHEMISTRY OF MATERIALS
2019; 31 (1): 90–100
View details for DOI 10.1021/acs.chemmater.8b03092
View details for Web of Science ID 000455558100011
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Dynamic Structure and Chemistry of the Silicon Solid-Electrolyte Interphase Visualized by Cryogenic Electron Microscopy
Matter
2019; 1 (5)
View details for DOI 10.1016/j.matt.2019.09.020
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Understanding the Mechanism of Electronic Defect Suppression Enabled by Nonidealities in Atomic Layer Deposition.
Journal of the American Chemical Society
2019
Abstract
Silicon germanium (SiGe) is a multifunctional material considered for quantum computing, neuromorphic devices, and CMOS transistors. However, implementation of SiGe in nanoscale electronic devices necessitates suppression of surface states dominating the electronic properties. The absence of a stable and passive surface oxide for SiGe results in the formation of charge traps at the SiGe-oxide interface induced by GeO x . In an ideal ALD process in which oxide is grown layer by layer, the GeO x formation should be prevented with selective surface oxidation (i.e., formation of an SiO x interface) by controlling the oxidant dose in the first few ALD cycles of the oxide deposition on SiGe. However, in a real ALD process, the interface evolves during the entire ALD oxide deposition due to diffusion of reactant species through the gate oxide. In this work, this diffusion process in nonideal ALD is investigated and exploited: the diffusion through the oxide during ALD is utilized to passivate the interfacial defects by employing ozone as a secondary oxidant. Periodic ozone exposure during gate oxide ALD on SiGe is shown to reduce the integrated trap density (Dit) across the band gap by nearly 1 order of magnitude in Al2O3 (<6 × 1010 cm-2) and in HfO2 (<3.9 × 1011 cm-2) by forming a SiO x -rich interface on SiGe. Depletion of Ge from the interfacial layer (IL) by enhancement of volatile GeO x formation and consequent desorption from the SiGe with ozone insertion during the ALD growth process is confirmed by electron energy loss spectroscopy (STEM-EELS) and hypothesized to be the mechanism for reduction of the interfacial defects. In this work, the nanoscale mechanism for defect suppression at the SiGe-oxide interface is demonstrated, which is engineering of diffusion species in the ALD process due to facile diffusion of reactant species in nonideal ALD.
View details for DOI 10.1021/jacs.9b06640
View details for PubMedID 31779305
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Silicon Photoanodes for Solar-Driven Oxidation of Brine: A Nanoscale, Photo-Active Analog of the Dimensionally-Stable Anode
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2018; 165 (16): H1072–H1079
View details for DOI 10.1149/2.0791816jes
View details for Web of Science ID 000454592800001
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Dynamic thermal emission control with InAs-based plasmonic metasurfaces.
Science advances
2018; 4 (12): eaat3163
Abstract
Thermal emission from objects tends to be spectrally broadband, unpolarized, and temporally invariant. These common notions are now challenged with the emergence of new nanophotonic structures and concepts that afford on-demand, active manipulation of the thermal emission process. This opens a myriad of new applications in chemistry, health care, thermal management, imaging, sensing, and spectroscopy. Here, we theoretically propose and experimentally demonstrate a new approach to actively tailor thermal emission with a reflective, plasmonic metasurface in which the active material and reflector element are epitaxially grown, high-carrier-mobility InAs layers. Electrical gating induces changes in the charge carrier density of the active InAs layer that are translated into large changes in the optical absorption and thermal emission from metasurface. We demonstrate polarization-dependent and electrically controlled emissivity changes of 3.6%P (6.5% in relative scale) in the mid-infrared spectral range.
View details for PubMedID 30539139
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Surface Defect Passivation of Silicon Micropillars
ADVANCED MATERIALS INTERFACES
2018; 5 (20)
View details for DOI 10.1002/admi.201800865
View details for Web of Science ID 000448787800017
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The Role of Catalyst Adhesion in ALD-TiO2 Protection of Water Splitting Silicon Anodes.
ACS applied materials & interfaces
2018
Abstract
Atomic layer deposited titanium dioxide (ALD-TiO2) has emerged as an effective protection layer for highly efficient semiconductor anodes which are normally unstable under the potential and pH conditions used to oxidize water in a photoelectrochemical cell. The failure modes of silicon anodes coated with an Ir/IrO x oxygen evolution catalyst layer are investigated, and poor catalyst/substrate adhesion is found to be a key factor in failed anodes. Quantitative measurements of interfacial adhesion energy show that the addition of TiO2 significantly improves reliability of anodes, yielding an adhesion energy of 6.02 ± 0.5 J/m2, more than double the adhesion energy measured in the absence of an ALD-TiO2 protection layer. These results indicate the importance of catalyst adhesion to an interposed protection layer in promoting operational stability of high efficiency semiconducting anodes during solar-driven water splitting.
View details for PubMedID 30346686
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Ultralow Defect Density at Sub-0.5 nm HfO2/SiGe Interfaces via Selective Oxygen Scavenging
ACS APPLIED MATERIALS & INTERFACES
2018; 10 (36): 30794–802
Abstract
The superior carrier mobility of SiGe alloys make them a highly desirable channel material in complementary metal-oxide-semiconductor (CMOS) transistors. Passivation of the SiGe surface and the associated minimization of interface defects between SiGe channels and high- k dielectrics continues to be a challenge for fabrication of high-performance SiGe CMOS. A primary source of interface defects is interfacial GeO x. This interfacial oxide can be decomposed using an oxygen-scavenging reactive gate metal, which nearly eliminates the interfacial oxides, thereby decreasing the amount of GeO x at the interface; the remaining ultrathin interlayer is consistent with a SiO x-rich interface. Density functional theory simulations demonstrate that a sub-0.5 nm thick SiO x-rich surface layer can produce an electrically passivated HfO2/SiGe interface. To form this SiO x-rich interlayer, metal gate stack designs including Al/HfO2/SiGe and Pd/Ti/TiN/nanolaminate (NL)/SiGe (NL: HfO2-Al2O3) were investigated. As compared to the control Ni-gated devices, those with Al/HfO2/SiGe gate stacks demonstrated more than an order of magnitude reduction in interface defect density with a sub-0.5 nm SiO x-rich interfacial layer. To further increase the oxide capacitance, the devices were fabricated with a Ti oxygen scavenging layer separated from the HfO2 by a conductive TiN diffusion barrier (remote scavenging). The Pd/Ti/TiN/NL/SiGe structures exhibited significant capacitance enhancement along with a reduction in interface defect density.
View details for PubMedID 30073827
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Atomic Layer Deposited TiO2-IrOx Alloy as a Hole Transport Material for Perovskite Solar Cells
ADVANCED MATERIALS INTERFACES
2018; 5 (16)
View details for DOI 10.1002/admi.201800191
View details for Web of Science ID 000442489600007
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Interfacial Cation-Defect Charge Dipoles in Stacked TiO2/Al2O3 Gate Dielectrics
ACS APPLIED MATERIALS & INTERFACES
2018; 10 (6): 5140–46
Abstract
Layered atomic-layer-deposited and forming-gas-annealed TiO2/Al2O3 dielectric stacks, with the Al2O3 layer interposed between the TiO2 and a p-type germanium substrate, are found to exhibit a significant interface charge dipole that causes a ∼-0.2 V shift of the flat-band voltage and suppresses the leakage current density for gate injection of electrons. These effects can be eliminated by the formation of a trilayer dielectric stack, consistent with the cancellation of one TiO2/Al2O3 interface dipole by the addition of another dipole of opposite sign. Density functional theory calculations indicate that the observed interface-dependent properties of TiO2/Al2O3 dielectric stacks are consistent in sign and magnitude with the predicted behavior of AlTi and TiAl point-defect dipoles produced by local intermixing of the Al2O3/TiO2 layers across the interface. Evidence for such intermixing is found in both electrical and physical characterization of the gate stacks.
View details for DOI 10.1021/acsami.7b19619
View details for Web of Science ID 000425572700003
View details for PubMedID 29369616
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Thermal Stability of Mixed Cation Metal Halide Perovskites in Air
ACS APPLIED MATERIALS & INTERFACES
2018; 10 (6): 5485–91
Abstract
We study the thermal stability in air of the mixed cation organic-inorganic lead halide perovskites Cs0.17FA0.83Pb(I0.83Br0.17)3 and Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3. For the latter compound, containing both MA+ and FA+ ions, thermal decomposition of the perovskite phase was observed to occur in two stages. The first stage of decomposition occurs at a faster rate compared to the second stage and is only observed at relatively low temperatures (T < 150 °C). For the second stage, we find that both decomposition rate and the activation energy have similar values for Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3 and Cs0.17FA0.83Pb(I0.83Br0.17)3, which suggests that the first stage mainly involves reaction of MA+ and the second stage mainly FA+.
View details for PubMedID 29328620
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Bias temperature stress induced hydrogen depassivation from Al2O3/InGaAs interface defects
JOURNAL OF APPLIED PHYSICS
2018; 123 (2)
View details for DOI 10.1063/1.4994393
View details for Web of Science ID 000422966100056
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Using liquid electrolytes in dielectric reliability studies
IEEE. 2018
View details for Web of Science ID 000444747600083
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Contact Selectivity Engineering in a 2 mum Thick Ultrathin c-Si Solar Cell Using Transition-Metal Oxides Achieving an Efficiency of 10.8.
ACS applied materials & interfaces
2017
Abstract
In this paper, the integration of metal oxides as carrier-selective contacts for ultrathin crystalline silicon (c-Si) solar cells is demonstrated which results in an 13% relative improvement in efficiency. The improvement in efficiency originates from the suppression of the contact recombination current due to the band offset asymmetry of these oxides with Si. First, an ultrathin c-Si solar cell having a total thickness of 2 mum is shown to have >10% efficiency without any light-trapping scheme. This is achieved by the integration of nickel oxide (NiOx) as a hole-selective contact interlayer material, which has a low valence band offset and high conduction band offset with Si. Second, we show a champion cell efficiency of 10.8% with the additional integration of titanium oxide (TiOx), a well-known material for an electron-selective contact interlayer. Key parameters including Voc and Jsc also show different degrees of enhancement if single (NiOx only) or double (both NiOx and TiOx) carrier-selective contacts are integrated. The fabrication process for TiOx and NiOx layer integration is scalable and shows good compatibility with the device.
View details for PubMedID 29124928
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Resistive Random Access Memory Cells with a Bilayer TiO2/SiOX Insulating Stack for Simultaneous Filamentary and Distributed Resistive Switching
ADVANCED FUNCTIONAL MATERIALS
2017; 27 (33)
View details for DOI 10.1002/adfm.201700384
View details for Web of Science ID 000409117500001
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Effects of H-2 High-pressure Annealing on HfO2/Al2O3/In0.53Ga0.47As Capacitors: Chemical Composition and Electrical Characteristics
SCIENTIFIC REPORTS
2017; 7: 9769
Abstract
We studied the impact of H2 pressure during post-metallization annealing on the chemical composition of a HfO2/Al2O3 gate stack on a HCl wet-cleaned In0.53Ga0.47As substrate by comparing the forming gas annealing (at atmospheric pressure with a H2 partial pressure of 0.04 bar) and H2 high-pressure annealing (H2-HPA at 30 bar) methods. In addition, the effectiveness of H2-HPA on the passivation of the interface states was compared for both p- and n-type In0.53Ga0.47As substrates. The decomposition of the interface oxide and the subsequent out-diffusion of In and Ga atoms toward the high-k film became more significant with increasing H2 pressure. Moreover, the increase in the H2 pressure significantly improved the capacitance‒voltage characteristics, and its effect was more pronounced on the p-type In0.53Ga0.47As substrate. However, the H2-HPA induced an increase in the leakage current, probably because of the out-diffusion and incorporation of In/Ga atoms within the high-k stack.
View details for PubMedID 28852035
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Distinguishing Oxygen Vacancy Electromigration and Conductive Filament Formation in TiO2 Resistance Switching Using Liquid Electrolyte Contacts.
Nano letters
2017; 17 (7): 4390-4399
Abstract
Resistance switching in TiO2 and many other transition metal oxide resistive random access memory materials is believed to involve the assembly and breaking of interacting oxygen vacancy filaments via the combined effects of field-driven ion migration and local electronic conduction leading to Joule heating. These complex processes are very difficult to study directly in part because the filaments form between metallic electrode layers that block their observation by most characterization techniques. By replacing the top electrode layer in a metal-insulator-metal memory structure with easily removable liquid electrolytes, either an ionic liquid (IL) with high resistance contact or a conductive aqueous electrolyte, we probe field-driven oxygen vacancy redistribution in TiO2 thin films under conditions that either suppress or promote Joule heating. Oxygen isotope exchange experiments indicate that exchange of oxygen ions between TiO2 and the IL is facile at room temperature. Oxygen loss significantly increases the conductivity of the TiO2 films; however, filament formation is not observed after IL gating alone. Replacing the IL with a more conductive aqueous electrolyte contact and biasing does produce electroformed conductive filaments, consistent with a requirement for Joule heating to enhance the vacancy concentration and mobility at specific locations in the film.
View details for DOI 10.1021/acs.nanolett.7b01460
View details for PubMedID 28604007
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Phase Field Model for Morphological Transition in Nanowire Vapor-Liquid-Solid Growth
CRYSTAL GROWTH & DESIGN
2017; 17 (4): 2211-2217
View details for DOI 10.1021/acs.cgd.7600197
View details for Web of Science ID 000398884400092
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Coexistence of Grain-Boundaries-Assisted Bipolar and Threshold Resistive Switching in Multilayer Hexagonal Boron Nitride
ADVANCED FUNCTIONAL MATERIALS
2017; 27 (10)
View details for DOI 10.1002/adfm.201604811
View details for Web of Science ID 000395717600006
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Interface Defect Hydrogen Depassivation and Capacitance-Voltage Hysteresis of Al2O3/InGaAs Gate Stacks
ACS APPLIED MATERIALS & INTERFACES
2017; 9 (8): 7819-7825
View details for DOI 10.1021/acsami.6b16232
View details for Web of Science ID 000395494200130
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Low temperature thermal ALD of a SiNx interfacial diffusion barrier and interface passivation layer on SixGe1-x(001) and SixGe1-x(110)
JOURNAL OF CHEMICAL PHYSICS
2017; 146 (5)
View details for DOI 10.1063/1.4975081
View details for Web of Science ID 000394576600022
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Electrochemical impedance spectroscopy for quantitative interface state characterization of planar and nanostructured semiconductor-dielectric interfaces.
Nanotechnology
2017; 28 (41): 415704
Abstract
The performance of nanostructured semiconductors is frequently limited by interface defects that trap electronic carriers. In particular, high aspect ratio geometries dramatically increase the difficulty of using typical solid-state electrical measurements (multifrequency capacitance- and conductance-voltage testing) to quantify interface trap densities (D it). We report on electrochemical impedance spectroscopy (EIS) to characterize the energy distribution of interface traps at metal oxide/semiconductor interfaces. This method takes advantage of liquid electrolytes, which provide conformal electrical contacts. Planar Al2O3/p-Si and Al2O3/p-Si0.55Ge0.45 interfaces are used to benchmark the EIS data against results obtained from standard electrical testing methods. We find that the solid state and EIS data agree very well, leading to the extraction of consistent D it energy distributions. Measurements carried out on pyramid-nanostructured p-Si obtained by KOH etching followed by deposition of a 10 nm ALD-Al2O3 demonstrate the application of EIS to trap characterization of a nanostructured dielectric/semiconductor interface. These results show the promise of this methodology to measure interface state densities for a broad range of semiconductor nanostructures such as nanowires, nanofins, and porous structures.
View details for PubMedID 28776501
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Core-Shell Germanium/Germanium Tin Nanowires Exhibiting Room Temperature Direct- and Indirect-Gap Photoluminescence
NANO LETTERS
2016; 16 (12): 7521-7529
Abstract
Germanium-tin alloy nanowires hold promise as silicon-compatible optoelectronic elements with the potential to achieve a direct band gap transition required for efficient light emission. In contrast to Ge1-xSnx epitaxial thin films, free-standing nanowires deposited on misfitting germanium or silicon substrates can avoid compressive, elastic strains that inhibit formation of a direct gap. We demonstrate strong room temperature photoluminescence, consistent with band edge emission from both Ge core nanowires, elastically strained in tension, and the almost unstrained Ge1-xSnx shells grown around them. Low-temperature chemical vapor deposition of these core-shell structures was achieved using standard precursors, resulting in Sn incorporation that significantly exceeds the bulk solubility limit in germanium.
View details for DOI 10.1021/acs.nanolett.6b03316
View details for PubMedID 27802056
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Temperature Dependent Border Trap Response Produced by a Defective Interfacial Oxide Layer in Al2O3/InGaAs Gate Stacks
ACS APPLIED MATERIALS & INTERFACES
2016; 8 (44): 30601-30607
View details for DOI 10.1021/acsami.6b10402
View details for Web of Science ID 000387737200085
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Isolating the Photovoltaic Junction: Atomic Layer Deposited TiO2-RuO2 Alloy Schottky Contacts for Silicon Photoanodes
ACS APPLIED MATERIALS & INTERFACES
2016; 8 (36): 23763-23773
Abstract
We synthesized nanoscale TiO2-RuO2 alloys by atomic layer deposition (ALD) that possess a high work function and are highly conductive. As such, they function as good Schottky contacts to extract photogenerated holes from n-type silicon while simultaneously interfacing with water oxidation catalysts. The ratio of TiO2 to RuO2 can be precisely controlled by the number of ALD cycles for each precursor. Increasing the composition above 16% Ru sets the electronic conductivity and the metal work function. No significant Ohmic loss for hole transport is measured as film thickness increases from 3 to 45 nm for alloy compositions ≥ 16% Ru. Silicon photoanodes with a 2 nm SiO2 layer that are coated by these alloy Schottky contacts having compositions in the range of 13-46% Ru exhibit average photovoltages of 525 mV, with a maximum photovoltage of 570 mV achieved. Depositing TiO2-RuO2 alloys on nSi sets a high effective work function for the Schottky junction with the semiconductor substrate, thus generating a large photovoltage that is isolated from the properties of an overlying oxygen evolution catalyst or protection layer.
View details for DOI 10.1021/acsami.6b08558
View details for Web of Science ID 000383412000036
View details for PubMedID 27548719
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Oxide Charge Engineering of Atomic Layer Deposited AlOxNy/Al2O3 Gate Dielectrics: A Path to Enhancement Mode GaN Devices.
ACS applied materials & interfaces
2016; 8 (32): 21089-21094
Abstract
Nitrogen incorporation to produce negative fixed charge in Al2O3 gate insulator layers is investigated as a path to achieve enhancement mode GaN device operation. A uniform distribution of nitrogen across the resulting AlOxNy films is obtained using N2 plasma enhanced atomic layer deposition (ALD). The flat band voltage (Vfb) increases to a significantly more positive value with increasing nitrogen concentration. Insertion of a 2 nm thick Al2O3 interlayer greatly decreases the trap density of the insulator/GaN interface, and reduces the voltage hysteresis and frequency dispersion of gate capacitance compared to single-layer AlOxNy gate insulators in GaN MOSCAPs.
View details for DOI 10.1021/acsami.6b03862
View details for PubMedID 27459343
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Characterization of the photocurrents generated by the laser of atomic force microscopes
REVIEW OF SCIENTIFIC INSTRUMENTS
2016; 87 (8)
Abstract
The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.
View details for DOI 10.1063/1.4960597
View details for Web of Science ID 000383880100034
View details for PubMedID 27587127
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Interface Engineering for Atomic Layer Deposited Alumina Gate Dielectric on SiGe Substrates.
ACS applied materials & interfaces
2016; 8 (29): 19110-19118
Abstract
Optimization of the interface between high-k dielectrics and SiGe substrates is a challenging topic due to the complexity arising from the coexistence of Si and Ge interfacial oxides. Defective high-k/SiGe interfaces limit future applications of SiGe as a channel material for electronic devices. In this paper, we identify the surface layer structure of as-received SiGe and Al2O3/SiGe structures based on soft and hard X-ray photoelectron spectroscopy. As-received SiGe substrates have native SiOx/GeOx surface layers, where the GeOx-rich layer is beneath a SiOx-rich surface. Silicon oxide regrows on the SiGe surface during Al2O3 atomic layer deposition, and both SiOx and GeOx regrow during forming gas anneal in the presence of a Pt gate metal. The resulting mixed SiOx-GeOx interface layer causes large interface trap densities (Dit) due to distorted Ge-O bonds across the interface. In contrast, we observe that oxygen-scavenging Al top gates decompose the underlying SiOx/GeOx, in a selective fashion, leaving an ultrathin SiOx interfacial layer that exhibits dramatically reduced Dit.
View details for DOI 10.1021/acsami.6b03331
View details for PubMedID 27345195
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Atomic Layer Deposited Corrosion Protection: A Path to Stable and Efficient Photoelectrochemical Cells.
journal of physical chemistry letters
2016; 7 (14): 2867-2878
Abstract
A fundamental challenge in developing photoelectrochemical cells for the renewable production of solar chemicals and fuels is the simultaneous requirement of efficient light absorption and robust stability under corrosive conditions. Schemes for corrosion protection of semiconductor photoelectrodes such as silicon using deposited layers were proposed and attempted for several decades, but increased operational lifetimes were either insufficient or the resulting penalties for device efficiency were prohibitive. In recent years, advances in atomic layer deposition (ALD) of thin coatings have made novel materials engineering possible, leading to substantial and simultaneous improvements in stability and efficiency of photoelectrochemical cells. The self-limiting, layer-by-layer growth of ALD makes thin films with low pinhole densities possible and may also provide a path to defect control that can generalize this protection technology to a large set of materials necessary to fully realize photoelectrochemical cell technology for artificial photosynthesis.
View details for DOI 10.1021/acs.jpclett.6b00631
View details for PubMedID 27359352
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Effects of Titanium Layer Oxygen Scavenging on the High-k/InGaAs Interface
ACS APPLIED MATERIALS & INTERFACES
2016; 8 (26): 16979-16984
Abstract
One of the main challenges in the path to incorporating InGaAs based metal-oxide-semiconductor structures in nanoelectronics is the passivation of high-k/InGaAs interfaces. Here, the oxygen scavenging effect of thin Ti layers on high-k/InGaAs gate stacks was studied. Electrical measurements and synchrotron X-ray photoelectron spectroscopy measurements, with in situ metal deposition, were used. Oxygen removal from the InGaAs native oxide surface layer remotely through interposed Al2O3 and HfO2 layers observed. Synchrotron X-ray photoelectron spectroscopy has revealed a decrease in the intensity of InOx features relative to In in InGaAs after Ti deposition. The signal ratio decreases further after annealing. In addition, Ti 2p spectra clearly show oxidation of the thin Ti layer in the ultrahigh vacuum XPS environment. Using capacitance-voltage and conductance-voltage measurements, Pt/Ti/Al2O3/InGaAs and Pt/Al2O3/InGaAs capacitors were characterized both before and after annealing. It was found that the remote oxygen scavenging from the oxide/semiconductor interface using a thin Ti layer can influence the density of interface traps in the high-k/InGaAs interface.
View details for DOI 10.1021/acsami.6b02957
View details for Web of Science ID 000379456000053
View details for PubMedID 27282201
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Titanium Oxide Crystallization and Interface Defect Passivation for High Performance Insulator-Protected Schottky Junction MIS Photoanodes
ACS APPLIED MATERIALS & INTERFACES
2016; 8 (23): 14596-14603
Abstract
Atomic layer deposited (ALD) TiO2 protection layers may allow for the development of both highly efficient and stable photoanodes for solar fuel synthesis; however, the very different conductivities and photovoltages reported for TiO2-protected silicon anodes prepared using similar ALD conditions indicate that mechanisms that set these key properties are, as yet, poorly understood. In this report, we study hydrogen-containing annealing treatments and find that postcatalyst-deposition anneals at intermediate temperatures reproducibly yield decreased oxide/silicon interface trap densities and high photovoltage. A previously reported insulator thickness-dependent photovoltage loss in metal-insulator-semiconductor Schottky junction photoanodes is suppressed. This occurs simultaneously with TiO2 crystallization and an increase in its dielectric constant. At small insulator thickness, a record for a Schottky junction photoanode of 623 mV photovoltage is achieved, yielding a photocurrent turn-on at 0.92 V vs NHE or -0.303 V with respect to the thermodynamic potential for water oxidation.
View details for DOI 10.1021/acsami.6b03688
View details for Web of Science ID 000378195000038
View details for PubMedID 27196628
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Engineering Interfacial Silicon Dioxide for Improved Metal-Insulator-Semiconductor Silicon Photoanode Water Splitting Performance
ACS APPLIED MATERIALS & INTERFACES
2016; 8 (20): 13140-13149
Abstract
Silicon photoanodes protected by atomic layer deposited (ALD) TiO2 show promise as components of water splitting devices that may enable the large-scale production of solar fuels and chemicals. Minimizing the resistance of the oxide corrosion protection layer is essential for fabricating efficient devices with good fill factor. Recent literature reports have shown that the interfacial SiO2 layer, interposed between the protective ALD-TiO2 and the Si anode, acts as a tunnel oxide that limits hole conduction from the photoabsorbing substrate to the surface oxygen evolution catalyst. Herein, we report a significant reduction of bilayer resistance, achieved by forming stable, ultrathin (<1.3 nm) SiO2 layers, allowing fabrication of water splitting photoanodes with hole conductances near the maximum achievable with the given catalyst and Si substrate. Three methods for controlling the SiO2 interlayer thickness on the Si(100) surface for ALD-TiO2 protected anodes were employed: (1) TiO2 deposition directly on an HF-etched Si(100) surface, (2) TiO2 deposition after SiO2 atomic layer deposition on an HF-etched Si(100) surface, and (3) oxygen scavenging, post-TiO2 deposition to decompose the SiO2 layer using a Ti overlayer. Each of these methods provides a progressively superior means of reliably thinning the interfacial SiO2 layer, enabling the fabrication of efficient and stable water oxidation silicon anodes.
View details for DOI 10.1021/acsami.6b03029
View details for Web of Science ID 000376825800069
View details for PubMedID 27096845
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Sulfur passivation for the formation of Si-terminated Al2O3/SiGe(001) interfaces
APPLIED SURFACE SCIENCE
2016; 366: 455-463
View details for DOI 10.1016/j.apsusc.2016.01.123
View details for Web of Science ID 000372517500056
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Spontaneous, Defect-Free Kinking via Capillary Instability during Vapor-Liquid-Solid Nanowire Growth.
Nano letters
2016; 16 (3): 1713-1718
Abstract
Kinking, a common anomaly in nanowire (NW) vapor-liquid-solid (VLS) growth, represents a sudden change of the wire's axial growth orientation. This study focuses on defect-free kinking during germanium NW VLS growth, after nucleation on a Ge (111) single crystal substrate, using Au-Ge catalyst liquid droplets of defined size. Statistical analysis of the fraction of kinked NWs reveals the dependence of kinking probability on the wire diameter and the growth temperature. The morphologies of kinked Ge NWs studied by electron microscopy show two distinct, defect-free, kinking modes, whose underlying mechanisms are explained with the help of 3D multiphase field simulations. Type I kinking, in which the growth axis changes from vertical [111] to ⟨110⟩, was observed in Ge NWs with a nominal diameter of ∼20 nm. This size coincides with a critical diameter at which a spontaneous transition from ⟨111⟩ to ⟨110⟩ growth occurs in the phase field simulations. Larger diameter NWs only exhibit Type II kinking, in which the growth axis changes from vertical [111] directly to an inclined ⟨111⟩ axis during the initial stages of wire growth. This is caused by an error in sidewall facet development, which produces a shrinkage in the area of the (111) growth facet with increasing NW length, causing an instability of the Au-Ge liquid droplet at the tip of the NW.
View details for DOI 10.1021/acs.nanolett.5b04633
View details for PubMedID 26837774
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From Twinning to Pure Zincblende Catalyst-Free InAs(Sb) Nanowires.
Nano letters
2016; 16 (1): 637-43
Abstract
III-V nanowires are candidate building blocks for next generation electronic and optoelectronic platforms. Low bandgap semiconductors such as InAs and InSb are interesting because of their high electron mobility. Fine control of the structure, morphology, and composition are key to the control of their physical properties. In this work, we present how to grow catalyst-free InAs1-xSbx nanowires, which are stacking fault and twin defect-free over several hundreds of nanometers. We evaluate the impact of their crystal phase purity by probing their electrical properties in a transistor-like configuration and by measuring the phonon-plasmon interaction by Raman spectroscopy. We also highlight the importance of high-quality dielectric coating for the reduction of hysteresis in the electrical characteristics of the nanowire transistors. High channel carrier mobilities and reduced hysteresis open the path for high-frequency devices fabricated using InAs1-xSbx nanowires.
View details for DOI 10.1021/acs.nanolett.5b04367
View details for PubMedID 26686394
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Nitride passivation of the interface between high-k dielectrics and SiGe
APPLIED PHYSICS LETTERS
2016; 108 (1)
View details for DOI 10.1063/1.4939460
View details for Web of Science ID 000374313000016
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Conductance and capacitance of bilayer protective oxides for silicon water splitting anodes
ENERGY & ENVIRONMENTAL SCIENCE
2016; 9 (2): 504-516
View details for DOI 10.1039/c5ee02484f
View details for Web of Science ID 000369744500017
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From Twinning to Pure Zincblende Catalyst-Free InAs(Sb) Nanowires
NANO LETTERS
2016; 16 (1): 637-643
View details for DOI 10.1021/acs.nanolett.5b04367
View details for Web of Science ID 000368322700097
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Design principles for maximizing photovoltage in metal-oxide-protected water-splitting photoanodes
NATURE MATERIALS
2016; 15 (1): 99-?
Abstract
Metal oxide protection layers for photoanodes may enable the development of large-scale solar fuel and solar chemical synthesis, but the poor photovoltages often reported so far will severely limit their performance. Here we report a novel observation of photovoltage loss associated with a charge extraction barrier imposed by the protection layer, and, by eliminating it, achieve photovoltages as high as 630 mV, the maximum reported so far for water-splitting silicon photoanodes. The loss mechanism is systematically probed in metal-insulator-semiconductor Schottky junction cells compared to buried junction p(+)n cells, revealing the need to maintain a characteristic hole density at the semiconductor/insulator interface. A leaky-capacitor model related to the dielectric properties of the protective oxide explains this loss, achieving excellent agreement with the data. From these findings, we formulate design principles for simultaneous optimization of built-in field, interface quality, and hole extraction to maximize the photovoltage of oxide-protected water-splitting anodes.
View details for DOI 10.1038/NMAT4451
View details for Web of Science ID 000366690600028
View details for PubMedID 26480231
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Understanding Photovoltage in Insulator-Protected Water Oxidation Half-Cells
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2016; 163 (3): H192-H200
View details for DOI 10.1149/2.0601603jes
View details for Web of Science ID 000370861500120
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Border trap reduction in Al2O3/InGaAs gate stacks
APPLIED PHYSICS LETTERS
2015; 107 (20)
View details for DOI 10.1063/1.4936100
View details for Web of Science ID 000365688700032
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The influence of surface preparation on low temperature HfO2 ALD on InGaAs (001) and (110) surfaces
JOURNAL OF CHEMICAL PHYSICS
2015; 143 (16)
View details for DOI 10.1063/1.4934656
View details for PubMedID 26520547
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Selective Passivation of GeO2/Ge Interface Defects in Atomic Layer Deposited High-k MOS Structures
ACS APPLIED MATERIALS & INTERFACES
2015; 7 (37): 20499-20506
View details for DOI 10.1021/acsami.5b06087
View details for Web of Science ID 000361931600002
View details for PubMedID 26334784
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Fermi level pinning in metal/Al2O3/InGaAs gate stack after post metallization annealing
JOURNAL OF APPLIED PHYSICS
2015; 118 (5)
View details for DOI 10.1063/1.4928158
View details for Web of Science ID 000359376700037
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Crystallization Pathway for Metastable Hexagonal Close-Packed Gold in Germanium Nanowire Catalysts
CRYSTAL GROWTH & DESIGN
2015; 15 (8): 3734-3739
View details for DOI 10.1021/acs.cgd.5b00803
View details for Web of Science ID 000359278800024
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Ultrafast Carrier Dynamics of a Photo-Excited Germanium Nanowire-Air Metamaterial
ACS PHOTONICS
2015; 2 (8): 1091-1098
View details for DOI 10.1021/acsphotonics.5b00147
View details for Web of Science ID 000359967400014
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Interface Trap Density Reduction for Al2O3/GaN (0001) Interfaces by Oxidizing Surface Preparation prior to Atomic Layer Deposition
ACS APPLIED MATERIALS & INTERFACES
2015; 7 (23): 12774-12780
Abstract
We correlate interfacial defect state densities with the chemical composition of the Al2O3/GaN interface in metal-oxide-semiconductor (MOS) structures using synchrotron photoelectron emission spectroscopy (PES), cathodoluminescence and high-temperature capacitance-voltage measurements. The influence of the wet chemical pretreatments involving (1) HCl+HF etching or (2) NH4OH(aq) exposure prior to atomic layer deposition (ALD) of Al2O3 were investigated on n-type GaN (0001) substrates. Prior to ALD, PES analysis of the NH4OH(aq) treated surface shows a greater Ga2O3 component compared to either HCl+HF treated or as-received surfaces. The lowest surface concentration of oxygen species is detected on the acid etched surface, whereas the NH4OH treated sample reveals the lowest carbon surface concentration. Both surface pretreatments improve electrical characteristics of MOS capacitors compared to untreated samples by reducing the Al2O3/GaN interface state density. The lowest interfacial trap density at energies in the upper band gap is detected for samples pretreated with NH4OH. These results are consistent with cathodoluminescence data indicating that the NH4OH treated samples show the strongest band edge emission compared to as-received and acid etched samples. PES results indicate that the combination of reduced carbon contamination while maintaining a Ga2O3 interfacial layer by NH4OH(aq) exposure prior to ALD results in fewer interface traps after Al2O3 deposition on the GaN substrate.
View details for DOI 10.1021/acsami.5b01600
View details for Web of Science ID 000356753500053
View details for PubMedID 25988586
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A Unified Two-Band Model for Oxide Traps and Interface States in MOS Capacitors
IEEE TRANSACTIONS ON ELECTRON DEVICES
2015; 62 (3): 813-820
View details for DOI 10.1109/TED.2015.2389805
View details for Web of Science ID 000350332000019
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Control of InGaAs and InAs facets using metal modulation epitaxy
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
2015; 33 (1)
View details for DOI 10.1116/1.4905497
View details for Web of Science ID 000348915500024
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Tailoring the Interface Quality between HfO2 and GaAs via in Situ ZnO Passivation Using Atomic Layer Deposition
ACS APPLIED MATERIALS & INTERFACES
2014; 6 (13): 10482-10488
Abstract
We investigated ZnO surface passivation of a GaAs (100) substrate using an atomic layer deposition (ALD) process to prepare an ultrathin ZnO layer prior to ALD-HfO2 gate dielectric deposition. Significant suppression of both Ga-O bond formation near the interface and As segregation at the interface was achieved. In addition, this method effectively suppressed the trapping of carriers in oxide defects with energies near the valence band edge of GaAs. According to electrical analyses of the interface state response on p- and n-type GaAs substrates, the interface states in the bottom half of the GaAs band gap were largely removed. However, the interface trap response in the top half of the band gap increased somewhat for the ZnO-passivated surface.
View details for DOI 10.1021/am502048d
View details for Web of Science ID 000338979900067
View details for PubMedID 24911531
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A three-dimensional phase field model for nanowire growth by the vapor-liquid-solid mechanism
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
2014; 22 (5)
View details for DOI 10.1088/0965-0393/22/5/055005
View details for Web of Science ID 000338441700006
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Ultrafast electron and phonon response of oriented and diameter-controlled germanium nanowire arrays.
Nano letters
2014; 14 (6): 3427-3431
Abstract
Carrier and phonon dynamics in dense arrays of aligned, single-crystal Ge nanowires (NWs) of controlled diameter are investigated by ultrafast optical pump-probe measurements, effective medium calculations, and elasticity analysis. Both a pronounced induced absorption and the amplitude and spectral range of Fabry-Perot oscillations observed in the probe signal are predicted for the NW array/air metamaterial by effective medium calculations. Detected temporal oscillations of reflectivity are consistent with excitation of radial breathing mode acoustic phonons by the intense pump pulse.
View details for DOI 10.1021/nl500953p
View details for PubMedID 24797453
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The effect of post oxide deposition annealing on the effective work function in metal/Al2O3/InGaAs gate stack
APPLIED PHYSICS LETTERS
2014; 104 (20)
View details for DOI 10.1063/1.4879246
View details for Web of Science ID 000337140800031
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Effects of oxide thickness and temperature on dispersions in InGaAs MOS C-V characteristics
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
2014; 32 (3)
View details for DOI 10.1116/1.4864618
View details for Web of Science ID 000337061900011
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Subcutaneous oxidation of In0.53Ga0.47As(100) through ultra-thin atomic layer deposited Al2O3
APPLIED PHYSICS LETTERS
2013; 103 (25)
View details for DOI 10.1063/1.4850520
View details for Web of Science ID 000329973800018
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Kinetics of germanium nanowire growth by the vapor-solid-solid mechanism with a Ni-based catalyst
APL MATERIALS
2013; 1 (6)
View details for DOI 10.1063/1.4833935
View details for Web of Science ID 000332280700002
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The Characterization and Passivation of Fixed Oxide Charges and Interface States in the Al2O3/InGaAs MOS System
IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY
2013; 13 (4): 429-443
View details for DOI 10.1109/TDMR.2013.2282216
View details for Web of Science ID 000328049700002
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Interface trap evaluation of Pd/Al2O3/GaN metal oxide semiconductor capacitors and the influence of near-interface hydrogen
APPLIED PHYSICS LETTERS
2013; 103 (20)
View details for DOI 10.1063/1.4827102
View details for Web of Science ID 000327818700027
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Comparison of Bulk-Oxide Trap Models: Lumped Versus Distributed Circuit
IEEE TRANSACTIONS ON ELECTRON DEVICES
2013; 60 (11): 3920-3924
View details for DOI 10.1109/TED.2013.2281298
View details for Web of Science ID 000326263200046
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Enhanced performance and endurance of nano-porous platinum solid oxide fuel cell electrodes by oxygen partial pressure cycling
MRS COMMUNICATIONS
2013; 3 (3): 123-128
View details for DOI 10.1557/mrc.2013.25
View details for Web of Science ID 000325095100002
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Arsenic decapping and pre-atomic layer deposition trimethylaluminum passivation of Al2O3/InGaAs(100) interfaces
APPLIED PHYSICS LETTERS
2013; 103 (7)
View details for DOI 10.1063/1.4818330
View details for Web of Science ID 000323769000012
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Effects of catalyst material and atomic layer deposited TiO2 oxide thickness on the water oxidation performance of metal-insulator-silicon anodes
ENERGY & ENVIRONMENTAL SCIENCE
2013; 6 (8): 2487-2496
View details for DOI 10.1039/c3ee41178h
View details for Web of Science ID 000321983800022
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Effects of surface oxide formation on germanium nanowire band-edge photoluminescence
APPLIED PHYSICS LETTERS
2013; 102 (25)
View details for DOI 10.1063/1.4812334
View details for Web of Science ID 000321145200022
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EOT Scaling of TiO2/Al2O3 on Germanium pMOSFETs and Impact of Gate Metal Selection
IEEE ELECTRON DEVICE LETTERS
2013; 34 (6): 732-734
View details for DOI 10.1109/LED.2013.2259137
View details for Web of Science ID 000319460800005
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New method for determining flat-band voltage in high mobility semiconductors
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
2013; 31 (3)
View details for DOI 10.1116/1.4802478
View details for Web of Science ID 000320130500040
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Effect and extraction of series resistance in Al2O3-InGaAs MOS with bulk-oxide trap
ELECTRONICS LETTERS
2013; 49 (7): 492-493
View details for DOI 10.1049/el.2013.0433
View details for Web of Science ID 000318549700035
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Enhanced Performance and Endurance of -Porous Platinum Solid Oxide Fuel Cell Electrodes by Oxygen Partial Pressure Cycling
MRS Comm.
2013
View details for DOI 10.1557/mrc.2013.25
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ALD-TiO2 Preparation and Characterization for Metal-Insulator-Silicon Photoelectrochemical Applications
9th International Symposium on Atomic Layer Deposition Applications held during the 224th Meeting of the Electrochemical-Society (ECS)
ELECTROCHEMICAL SOC INC. 2013: 75–86
View details for DOI 10.1149/05810.0075ecst
View details for Web of Science ID 000329647500008
- New Method for Determining Flat-Band Voltage in High Mobility Semiconductors J. Vac. Sci. Technol. B 2013; 31: 30604
- Arsenic Decapping and Pre-ALD Trimethylaluminum Passivation of Al2O3/InGaAs(100) Interfaces Appl. Phys. Lett. 2013; 103: 071602-1-4
- EOT Scaling of TiO2/Al2O3 on Germanium pMOSFETs and Impact of Gate Metal Selection IEEE Electron Dev. Lett. 2013; 34: 732-34
- Effect and Extraction of Series Resistance in Al2O3-InGaAs MOS with Bulk-Oxide Trap Electronics Lett. 2013; 49: 492-93
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Temperature-dependent capacitance-voltage analysis of defects in Al2O3 gate dielectric stacks on GaN
APPLIED PHYSICS LETTERS
2012; 101 (24)
View details for DOI 10.1063/1.4769827
View details for Web of Science ID 000312490000025
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Directed synthesis of germanium oxide nanowires by vapor-liquid-solid oxidation
NANOTECHNOLOGY
2012; 23 (38)
Abstract
We report on the directed synthesis of germanium oxide (GeO(x)) nanowires (NWs) by locally catalyzed thermal oxidation of aligned arrays of gold catalyst-tipped germanium NWs. During oxygen anneals conducted above the Au-Ge binary eutectic temperature (T > 361 °C), one-dimensional oxidation of as-grown Ge NWs occurs by diffusion of Ge through the Au-Ge catalyst droplet, in the presence of an oxygen containing ambient. Elongated GeO(x) wires grow from the liquid catalyst tip, consuming the adjoining Ge NWs as they grow. The oxide NWs' diameter is dictated by the catalyst diameter and their alignment generally parallels that of the growth direction of the initial Ge NWs. Growth rate comparisons reveal a substantial oxidation rate enhancement in the presence of the Au catalyst. Statistical analysis of GeO(x) nanowire growth by ex situ transmission electron microscopy and scanning electron microscopy suggests a transition from an initial, diameter-dependent kinetic regime, to diameter-independent wire growth. This behavior suggests the existence of an incubation time for GeO(x) NW nucleation at the start of vapor-liquid-solid oxidation.
View details for DOI 10.1088/0957-4484/23/38/385603
View details for Web of Science ID 000308813100019
View details for PubMedID 22947505
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Interface-State Modeling of Al2O3-InGaAs MOS From Depletion to Inversion
IEEE TRANSACTIONS ON ELECTRON DEVICES
2012; 59 (9): 2383-2389
View details for DOI 10.1109/TED.2012.2205255
View details for Web of Science ID 000307905200017
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Size effects in vapor-solid-solid Ge nanowire growth with a Ni-based catalyst
JOURNAL OF APPLIED PHYSICS
2012; 112 (5)
View details for DOI 10.1063/1.4749797
View details for Web of Science ID 000309072200138
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A Distributed Bulk-Oxide Trap Model for Al2O3 InGaAs MOS Devices
IEEE TRANSACTIONS ON ELECTRON DEVICES
2012; 59 (8): 2100-2106
View details for DOI 10.1109/TED.2012.2197000
View details for Web of Science ID 000306920200015
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Direct-gap photoluminescence from germanium nanowires
PHYSICAL REVIEW B
2012; 86 (3)
View details for DOI 10.1103/PhysRevB.86.035306
View details for Web of Science ID 000306189300005
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Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices
MATERIALS
2012; 5 (7): 1297-1335
View details for DOI 10.3390/ma5071297
View details for Web of Science ID 000306750400011
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Admittance and subthreshold characteristics of atomic-layer-deposition Al2O3 on In0.53Ga0.47As in surface and buried channel flatband metal-oxide-semiconductor field effect transistors
AMER INST PHYSICS. 2012
View details for DOI 10.1063/1.4720940
View details for Web of Science ID 000305363700119
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Thermal Stability and Surface Passivation of Ge Nanowires Coated by Epitaxial SiGe Shells
NANO LETTERS
2012; 12 (3): 1385-1391
Abstract
Epitaxial growth of a highly strained, coherent SiGe alloy shell around a Ge nanowire core is investigated as a method to achieve surface passivation and carrier confinement, important in realizing nanowire devices. The high photoluminescence intensity observed from the core-shell nanowires with spectral features similar to that of bulk Ge indicates effective surface passivation. Thermal stability of these core-shell heterostructures has been systematically investigated, with a method demonstrated to avoid misfit strain relaxation during postgrowth annealing.
View details for DOI 10.1021/nl204053w
View details for Web of Science ID 000301406800046
View details for PubMedID 22364183
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Nucleation and growth kinetics during metal-induced layer exchange crystallization of Ge thin films at low temperatures
JOURNAL OF APPLIED PHYSICS
2012; 111 (4)
View details for DOI 10.1063/1.3682110
View details for Web of Science ID 000300948600130
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Erratum: Charged Defect Quantification in Pt/Al2O3/In0.53Ga0.47As/InP MOS Capacitors (vol 158, pg G103, 2011)
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2012; 159 (6): S17-S17
View details for DOI 10.1149/2.119206jes
View details for Web of Science ID 000304140700092
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Mechanism of Dangling Bond Elimination on As-rich InGaAs Surface
IEEE International Electron Devices Meeting (IEDM)
IEEE. 2012
View details for Web of Science ID 000320615600195
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Undoped Ge Core-Si(Ge) Shell Nanowires: Synthesis, Local Composition and Strain Characterization
5th SiGe, Ge, and Related Compounds - Materials, Processing and Devices Symposium held at the 220th Meeting of the Electrochemical-Society (ECS)
ELECTROCHEMICAL SOC INC. 2012: 635–43
View details for DOI 10.1149/05009.0635ecst
View details for Web of Science ID 000338015300074
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In-situ As-2 decapping and atomic layer deposition of Al2O3 on n-InGaAs(100)
4th International Symposium on Graphene, Ge/III-V and Emerging Materials For Post-CMOS Applications held at the 221st Meeting of the Electrochemical-Society (ECS) as Symposium E2
ELECTROCHEMICAL SOC INC. 2012: 183–88
View details for DOI 10.1149/1.3701133
View details for Web of Science ID 000316890000021
- In-Situ As2 Decapping and Atomic Layer Deposition of Al2O3 on n-InGaAs(100) 2012
- Undoped Ge Core-Si(Ge) Shell Nanowires: Synthesis, Local Composition and Strain 2012
- Mechanism of Dangling Bond Elimination on As-rich InGaAs Surface 2012
- Interface-State Modeling of Al2O3–InGaAs MOS From Depletion to Inversion IEEE Trans. Electron Dev. 2012; 59: 2383-89
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Titania/alumina bilayer gate insulators for InGaAs metal-oxide-semiconductor devices
APPLIED PHYSICS LETTERS
2011; 99 (23)
View details for DOI 10.1063/1.3662966
View details for Web of Science ID 000298006100054
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Ultrathin ALD-Al2O3 layers for Ge(001) gate stacks: Local composition evolution and dielectric properties
JOURNAL OF APPLIED PHYSICS
2011; 110 (9)
View details for DOI 10.1063/1.3647761
View details for Web of Science ID 000297062100087
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Introduction
JOURNAL OF MATERIALS RESEARCH
2011; 26 (17): 2125-2126
View details for DOI 10.1557/jmr.2011.235
View details for Web of Science ID 000296083100001
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Mobile Ferroelastic Domain Walls in Nanocrystalline PZT Films: the Direct Piezoelectric Effect
ADVANCED FUNCTIONAL MATERIALS
2011; 21 (16): 3104-3110
View details for DOI 10.1002/adfm.201100445
View details for Web of Science ID 000294166200011
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III-V nMOSFETs - Some issues associated with roadmap worthiness (invited)
17th International Conference on Insulating Films on Semiconductors
ELSEVIER SCIENCE BV. 2011: 1070–75
View details for DOI 10.1016/j.mee.2011.03.100
View details for Web of Science ID 000292572700008
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Atomic layer-deposited tunnel oxide stabilizes silicon photoanodes for water oxidation
NATURE MATERIALS
2011; 10 (7): 539-544
Abstract
A leading approach for large-scale electrochemical energy production with minimal global-warming gas emission is to use a renewable source of electricity, such as solar energy, to oxidize water, providing the abundant source of electrons needed in fuel synthesis. We report corrosion-resistant, nanocomposite anodes for the oxidation of water required to produce renewable fuels. Silicon, an earth-abundant element and an efficient photovoltaic material, is protected by atomic layer deposition (ALD) of a highly uniform, 2 nm thick layer of titanium dioxide (TiO(2)) and then coated with an optically transmitting layer of a known catalyst (3 nm iridium). Photoelectrochemical water oxidation was observed to occur below the reversible potential whereas dark electrochemical water oxidation was found to have low-to-moderate overpotentials at all pH values, resulting in an inferred photovoltage of ~550 mV. Water oxidation is sustained at these anodes for many hours in harsh pH and oxidative environments whereas comparable silicon anodes without the TiO(2) coating quickly fail. The desirable electrochemical efficiency and corrosion resistance of these anodes is made possible by the low electron-tunnelling resistance (<0.006 Ω cm(2) for p(+)-Si) and uniform thickness of atomic-layer deposited TiO(2).
View details for DOI 10.1038/NMAT3047
View details for Web of Science ID 000291969500020
View details for PubMedID 21685904
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A Distributed Model for Border Traps in Al2O3 - InGaAs MOS Devices
IEEE ELECTRON DEVICE LETTERS
2011; 32 (4): 485-487
View details for DOI 10.1109/LED.2011.2105241
View details for Web of Science ID 000288664800019
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Electron Mobility in Surface- and Buried-Channel Flatband In0.53Ga0.47As MOSFETs With ALD Al2O3 Gate Dielectric
IEEE ELECTRON DEVICE LETTERS
2011; 32 (4): 494-496
View details for DOI 10.1109/LED.2011.2107876
View details for Web of Science ID 000288664800022
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Inelastic electron tunneling study of crystallization effects and defect energies in hafnium oxide gate dielectrics
APPLIED PHYSICS LETTERS
2011; 98 (3)
View details for DOI 10.1063/1.3527977
View details for Web of Science ID 000286471100026
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Morphological Stability of Mesoporous Pt Thin Films Deposited via Nanosphere Lithography on YSZ (vol 14, pg B96, 2011)
ELECTROCHEMICAL AND SOLID STATE LETTERS
2011; 14 (11): S9-S9
View details for DOI 10.1149/2.010111esl
View details for Web of Science ID 000295284800025
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Strain relaxation mechanisms in compressively strained thin SiGe-on-insulator films grown by selective Si oxidation
JOURNAL OF APPLIED PHYSICS
2011; 109 (1)
View details for DOI 10.1063/1.3506420
View details for Web of Science ID 000286219300130
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Morphological Stability of Mesoporous Pt Thin Films Deposited via Nanosphere Lithography on YSZ
ELECTROCHEMICAL AND SOLID STATE LETTERS
2011; 14 (10): B96-B99
View details for DOI 10.1149/1.3609257
View details for Web of Science ID 000295211600008
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Charged Defect Quantification in Pt/Al2O3/In0.53Ga0.47As/InP MOS Capacitors
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2011; 158 (5): G103-G107
View details for DOI 10.1149/1.3545799
View details for Web of Science ID 000288867700071
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The changing landscape of conservation science funding in the United States
CONSERVATION LETTERS
2010; 3 (6): 435-444
View details for DOI 10.1111/j.1755-263X.2010.00125.x
View details for Web of Science ID 000284893700008
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Modified phonon confinement model for Raman spectroscopy of nanostructured materials
PHYSICAL REVIEW B
2010; 82 (11)
View details for DOI 10.1103/PhysRevB.82.115210
View details for Web of Science ID 000282007600004
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Hexagonal Close-Packed Structure of Au Nanocatalysts Solidified after Ge Nanowire Vapor-Liquid-Solid Growth
NANO LETTERS
2010; 10 (9): 3302-3306
Abstract
We report that approximately 10% of the Au catalysts that crystallize at the tips of Ge nanowires following growth have the close-packed hexagonal crystal structure rather than the equilibrium face-centered-cubic structure. Transmission electron microscopy results using aberration-corrected imaging, and diffraction and compositional analyses, confirm the hexagonal phase in these 40-50 nm particles. Reports of hexagonal close packing in Au, even in nanoparticle form, are rare, and the observations suggest metastable pathways for the crystallization process. These results bring new considerations to the stabilization of the liquid eutectic alloy at low temperatures that allows for vapor-liquid-solid growth of high quality, epitaxial Ge nanowires below the eutectic temperature.
View details for DOI 10.1021/nl100913d
View details for Web of Science ID 000281498200014
View details for PubMedID 20687570
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High temperature electrical conduction in nanoscale hafnia films under varying oxygen partial pressure
APPLIED PHYSICS LETTERS
2010; 97 (8)
View details for DOI 10.1063/1.3482940
View details for Web of Science ID 000281306500032
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Interface-controlled layer exchange in metal-induced crystallization of germanium thin films
APPLIED PHYSICS LETTERS
2010; 97 (8)
View details for DOI 10.1063/1.3480600
View details for Web of Science ID 000281306500034
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Arsenic decapping and half cycle reactions during atomic layer deposition of Al2O3 on In0.53Ga0.47As(001)
APPLIED PHYSICS LETTERS
2010; 96 (25)
View details for DOI 10.1063/1.3452336
View details for Web of Science ID 000279168100045
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Gold-Catalyzed Vapor-Liquid-Solid Germanium-Nanowire Nucleation on Porous Silicon
SMALL
2010; 6 (9): 1032-1037
Abstract
Nanoporous Si(111) substrates are used to study the effects of Au catalyst coarsening on the nucleation of vapor-liquid-solid-synthesized epitaxial Ge nanowires (NWs) at temperatures less than 400 degrees C. Porous Si substrates, with greater effective interparticle separations for Au surface diffusion than nonporous Si, inhibit catalyst coarsening and agglomeration prior to NW nucleation. This greatly reduces the variation in wire diameter and length and increases the yield compared to nucleation on identically prepared nonporous Si substrates.
View details for DOI 10.1002/smll.200901764
View details for Web of Science ID 000278437500008
View details for PubMedID 20411571
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Origin and passivation of fixed charge in atomic layer deposited aluminum oxide gate insulators on chemically treated InGaAs substrates
APPLIED PHYSICS LETTERS
2010; 96 (15)
View details for DOI 10.1063/1.3399776
View details for Web of Science ID 000276794100054
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Bilayer metal oxide gate insulators for scaled Ge-channel metal-oxide-semiconductor devices
APPLIED PHYSICS LETTERS
2010; 96 (8)
View details for DOI 10.1063/1.3313946
View details for Web of Science ID 000275027200064
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Group IV semiconductor nanowire arrays: epitaxy in different contexts
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
2010; 25 (2)
View details for DOI 10.1088/0268-1242/25/2/024016
View details for Web of Science ID 000273852300017
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Border traps in Al2O3/In0.53Ga0.47As (100) gate stacks and their passivation by hydrogen anneals
APPLIED PHYSICS LETTERS
2010; 96 (1)
View details for DOI 10.1063/1.3281027
View details for Web of Science ID 000273473200037
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Titania/Alumina Bilayer Gate Dielectrics for Ge MOS Devices: Frequency- and Temperature-Dependent Electrical Characteristics
ELECTROCHEMICAL AND SOLID STATE LETTERS
2010; 13 (9): G79-G82
View details for DOI 10.1149/1.3457480
View details for Web of Science ID 000279806700016
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III-V MOSFETs: Scaling Laws, Scaling Limits, Fabrication Processes
22nd International Conference on Indium Phosphide and Related Materials
IEEE. 2010
View details for Web of Science ID 000287417700003
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In Situ XPS in Atomic Layer Deposition of Oxides on Ge (100)
4th SiGe, Ge, and Related Compounds - Materials, Processing and Devices Symposium held at the 218th Meeting of the Electrochemical-Society (ECS)
ELECTROCHEMICAL SOC INC. 2010: 455–62
View details for DOI 10.1149/1.3487576
View details for Web of Science ID 000314957600047
- Gold-Catalyzed Vapor–Liquid–Solid Germanium-Nanowire Nucleation on Porous Silicon Small 2010; 6: 1032-37
- Arsenic Decapping and Half-Cycle Reactions during Atomic Layer Deposition of Al2O3 on In0.53Ga0.47As (001) Appl. Phys. Lett. 2010; 96: 252907-1-3
- In Situ XPS in Atomic Layer Deposition of Oxides on Ge (100) 2010
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DESIGN AND GROWTH OF III-V NANOWIRE SOLAR CELL ARRAYS ON LOW COST SUBSTRATES
35th IEEE Photovoltaic Specialists Conference
IEEE. 2010: 2034–2037
View details for Web of Science ID 000287579502062
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FACETING AND DISORDER IN NANOWIRE SOLAR CELL ARRAYS
35th IEEE Photovoltaic Specialists Conference
IEEE. 2010: 1848–1853
View details for Web of Science ID 000287579502020
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Atomic Layer Deposited Hafnium Oxide Gate Dielectrics for Charge-Based Biosensors
ELECTROCHEMICAL AND SOLID STATE LETTERS
2010; 13 (3): G29-G32
View details for DOI 10.1149/1.3280224
View details for Web of Science ID 000273690400014
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Atomically abrupt and unpinned Al2O3/In0.53Ga0.47As interfaces: Experiment and simulation
JOURNAL OF APPLIED PHYSICS
2009; 106 (12)
View details for DOI 10.1063/1.3266006
View details for Web of Science ID 000273216500098
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Thermal Properties of Ultrathin Hafnium Oxide Gate Dielectric Films
IEEE ELECTRON DEVICE LETTERS
2009; 30 (12): 1269-1271
View details for DOI 10.1109/LED.2009.2032937
View details for Web of Science ID 000272044500007
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Inhibiting Strain-Induced Surface Roughening: Dislocation-Free Ge/Si and Ge/SiGe Core-Shell Nanowires
NANO LETTERS
2009; 9 (11): 3715-3719
Abstract
Elastic strain is a critical factor in engineering the electronic behavior of core-shell semiconductor nanowires and provides the driving force for undesirable surface roughening and defect formation. We demonstrate two independent strategies, chlorine surface passivation and growth of nanowires with low-energy sidewall facets, to avoid strain-induced surface roughening that promotes dislocation nucleation in group IV core-shell nanowires. Metastably strained, dislocation-free, core-shell nanowires are obtained, and axial strains are measured and compared to elasticity model predictions.
View details for DOI 10.1021/nl9018148
View details for Web of Science ID 000271566400009
View details for PubMedID 19795838
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In0.53Ga0.47As Channel MOSFETs With Self-Aligned InAs Source/Drain Formed by MEE Regrowth
IEEE ELECTRON DEVICE LETTERS
2009; 30 (11): 1128-1130
View details for DOI 10.1109/LED.2009.2031304
View details for Web of Science ID 000271151500004
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Size-dependent polymorphism in HfO2 nanotubes and nanoscale thin films
JOURNAL OF APPLIED PHYSICS
2009; 106 (8)
View details for DOI 10.1063/1.3243077
View details for Web of Science ID 000271358100097
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Single-crystal germanium layers grown on silicon by nanowire seeding
NATURE NANOTECHNOLOGY
2009; 4 (10): 649-653
Abstract
Three-dimensional integration and the combination of different material systems are central themes of electronics research. Recently, as-grown vertical one-dimensional structures have been integrated into high-density three-dimensional circuits. However, little attention has been paid to the unique structural properties of germanium nanowires obtained by epitaxial and heteroepitaxial growth on Ge(111) and Si(111) substrates, despite the fact that the integration of germanium on silicon is attractive for device applications. Here, we demonstrate the lateral growth of single crystal germanium islands tens of micrometres in diameter by seeding from germanium nanowires grown on a silicon substrate. Vertically aligned high-aspect-ratio nanowires can transfer the orientation and perfection of the substrate crystal to overlying layers a micrometre or more above the substrate surface. This technique can be repeated to build multiple active device layers, a key requirement for the fabrication of densely interconnected three-dimensional integrated circuits.
View details for DOI 10.1038/nnano.2009.233
View details for Web of Science ID 000270513900016
View details for PubMedID 19809455
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Gold Removal from Germanium Nanowires
LANGMUIR
2009; 25 (16): 9473-9479
Abstract
We report the selective removal of gold from the tips of germanium nanowires (GeNWs) grown by chemical vapor deposition on gold nanoparticles (AuNPs). Selective removal was accomplished by aqueous hydrochloric acid solutions containing either potassium triiodide or iodine. Measurement of the residual number of gold atoms on the GeNW samples using inductively coupled plasma-mass spectrometry shows that 99% of the gold was removed. Photoemission spectroscopy shows that the germanium surfaces of these samples were not further oxidized after treatment with these liquid etchants. Auger electron spectroscopy shows that AuNPs that did not yield GeNWs contain germanium and also that the addition of gaseous HCl to GeH(4) during GeNW growth increased the selectivity of germanium deposition to the AuNPs.
View details for DOI 10.1021/la900725b
View details for Web of Science ID 000268719900088
View details for PubMedID 19419180
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Oxidant prepulsing of Ge (100) prior to atomic layer deposition of Al2O3: In situ surface characterization
APPLIED PHYSICS LETTERS
2009; 95 (3)
View details for DOI 10.1063/1.3177195
View details for Web of Science ID 000268405300051
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Atomic Layer Deposition of Dielectrics on Ge and III-V Materials for Ultrahigh Performance Transistors
MRS BULLETIN
2009; 34 (7): 493-503
View details for Web of Science ID 000268159400015
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Nanowires for Energy Applications: Fundamental Growth Studies
CAMBRIDGE UNIV PRESS. 2009: 144–145
View details for DOI 10.1017/S1431927609094641
View details for Web of Science ID 000208119100072
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Interface studies of ALD-grown metal oxide insulators on Ge and III-V semiconductors
16th Biennial Conference on Insulating Films on Semiconductors
ELSEVIER SCIENCE BV. 2009: 1536–39
View details for DOI 10.1016/j.mee.2009.03.081
View details for Web of Science ID 000267460100004
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Hafnium oxide/germanium oxynitride gate stacks on germanium: Capacitance scaling and interface state density
APPLIED PHYSICS LETTERS
2009; 94 (18)
View details for DOI 10.1063/1.3116624
View details for Web of Science ID 000265933700046
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High-quality III-V semiconductor MBE growth on Ge/Si virtual substrates for metal-oxide-semiconductor device fabrication
JOURNAL OF CRYSTAL GROWTH
2009; 311 (7): 1962-1971
View details for DOI 10.1016/j.jcrysgro.2008.09.138
View details for Web of Science ID 000265659300083
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Growth of germanium crystals from electrodeposited gold in local crucibles
APPLIED PHYSICS LETTERS
2009; 94 (4)
View details for DOI 10.1063/1.3074363
View details for Web of Science ID 000262971800124
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Vertical Germanium Nanowire Arrays in Microfluidic Channels for Charged Molecule Detection
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2009; 156 (2): K11-K16
View details for DOI 10.1149/1.3033522
View details for Web of Science ID 000261973600052
- Group IV semiconductor nanowire arrays: Different flavors of epitaxy 2009
- Interface Studies of ALD-Grown Metal Oxide Insulators on Ge and III–V Semiconductors Microelectron. Engineering 2009; 86: 1536–39
- High-Quality III–V Semiconductor MBE Growth on Ge/Si Virtual Substrates for Metal-Oxide-Semiconductor Device Fabrication J. Crystal Growth 2009; 311: 1962-71
- Unpinned Interface Between Al2O3 Gate Dielectric Layer Grown by AtomicLayer Deposition and Chemically Treated n-In0.53Ga0.47As (001) Electrochem. Solid-State Lett. 2009; 12: G40-43
- Atomically Abrupt and Unpinned Al2O3/ In0.53Ga0.47As Interfaces: Experiment and Simulation J. Appl. Phys. 2009; 106: 124508-1-8
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Enhancement Mode In0.53Ga0.47As MOSFET with self-aligned epitaxial Source/Drain regrowth
21st International Conference on Indium Phosphide and Related Materials
IEEE. 2009: 120–123
View details for Web of Science ID 000270539400032
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Unpinned Interface Between Al2O3 Gate Dielectric Layer Grown by Atomic Layer Deposition and Chemically Treated n-In0.53Ga0.47As(001)
ELECTROCHEMICAL AND SOLID STATE LETTERS
2009; 12 (8): G40-G43
View details for DOI 10.1149/1.3139603
View details for Web of Science ID 000266975000013
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Oxide-encapsulated vertical germanium nanowire structures and their DC transport properties
NANOTECHNOLOGY
2008; 19 (48)
Abstract
We demonstrate the p-type doping of Ge nanowires (NWs) and p-n junction arrays in a scalable vertically aligned structure with all processing performed below 400 °C. These structures are advantageous for the large scale production of parallel arrays of devices for nanoelectronics and sensing applications. Efficient methods for the oxide encapsulation, chemical mechanical polishing and cleaning of vertical Ge NWs embedded in silicon dioxide are reported. Approaches for avoiding the selective oxidation and dissolution of Ge NWs in aqueous solutions during chemical mechanical polishing and cleaning of oxide-encapsulated Ge NWs are emphasized. NWs were doped through the epitaxial deposition of a B-doped shell and transport measurements indicate doping concentrations on the order of 10(19) cm(-3).
View details for DOI 10.1088/0957-4484/19/48/485705
View details for Web of Science ID 000260859400022
View details for PubMedID 21836312
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Synthesis and Strain Relaxation of Ge-Core/Si-Shell Nanowire Arrays
NANO LETTERS
2008; 8 (11): 4081-4086
Abstract
Analogous to planar heteroepitaxy, misfit dislocation formation and stress-driven surface roughening can relax coherency strains in misfitting core-shell nanowires. The effects of coaxial dimensions on strain relaxation in aligned arrays of Ge-core/Si-shell nanowires are analyzed quantitatively by transmission electron microscopy and synchrotron X-ray diffraction. Relating these results to reported continuum elasticity models for coaxial nanowire heterostructures provides valuable insights into the observed interplay of roughening and dislocation-mediated strain relaxation.
View details for DOI 10.1021/nl802408y
View details for Web of Science ID 000260888600094
View details for PubMedID 18954126
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Analysis of electrically biased paramagnetic defect centers in HfO2 and HfxSi1-xO2/(100)Si interfaces
JOURNAL OF APPLIED PHYSICS
2008; 104 (1)
View details for DOI 10.1063/1.2948922
View details for Web of Science ID 000257766500104
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Morphological instability of misfit-strained core-shell nanowires
PHYSICAL REVIEW B
2008; 77 (23)
View details for DOI 10.1103/PhysRevB.77.235302
View details for Web of Science ID 000257289500069
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Molecular-beam epitaxial growth of III-V semiconductors on Ge/Si for metal-oxide-semiconductor device fabrication
APPLIED PHYSICS LETTERS
2008; 92 (20)
View details for DOI 10.1063/1.2929386
View details for Web of Science ID 000256196600093
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Silicon-germanium interdiffusion in high-germanium-content epitaxial heterostructures
APPLIED PHYSICS LETTERS
2008; 92 (18)
View details for DOI 10.1063/1.2917798
View details for Web of Science ID 000256485700022
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Ge-interface engineering with ozone oxidation for low interface-state density
IEEE ELECTRON DEVICE LETTERS
2008; 29 (4): 328-330
View details for DOI 10.1109/LED.2008.918272
View details for Web of Science ID 000254225800015
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HfO2 gate dielectric on (NH4)(2)S passivated (100) GaAs grown by atomic layer deposition
JOURNAL OF APPLIED PHYSICS
2008; 103 (3)
View details for DOI 10.1063/1.2838471
View details for Web of Science ID 000253238100054
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Selective oxidation of SiGe alloys: A route to Ge-on-insulator structures with controlled biaxial strain
ELECTROCHEMICAL AND SOLID STATE LETTERS
2008; 11 (6): H138-H142
View details for DOI 10.1149/1.2896080
View details for Web of Science ID 000255117500022
- Chemical Bonding, Interfaces, and Defects in Hafnium Oxide/Germanium Oxynitride Gate Stacks on Ge(100) J. Electrochem. Soc. 2008; 155: G304-09
- HfO2 Gate Dielectric on (NH4)2S Passivated (100) GaAs Grown by Atomic Layer Deposition J. Appl. Phys. 2008; 103: 34106
- Analysis of Electrically Biased Paramagnetic Defect Centers in HfO2 and HfxSi1−xO2 /(100) Si Interfaces J. Appl. Phys. 2008; 104: 14106
- Pre-Atomic Layer Deposition Surface Cleaning and Chemical Passivation of (100) In0.2Ga0.8As and Deposition of Ultrathin Al2O3 Gate insulators Appl. Phys. Lett. 2008; 93: 052911-1-3
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Ge Interface Passivation Techniques and Their Thermal Stability
3rd International SiGe, Ge and Related Compounds Symposium
ELECTROCHEMICAL SOCIETY INC. 2008: 1025–29
View details for DOI 10.1149/1.2986865
View details for Web of Science ID 000273336700114
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Atomic Layer Deposition of Hafnium Oxide on Ge and GaAs Substrates: Precursors and Surface Preparation
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2008; 155 (12): H937-H944
View details for DOI 10.1149/1.2979144
View details for Web of Science ID 000260479700068
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Effects of chemical stability of platinum/lead zirconate titanate and iridium oxide/lead zirconate titanate interfaces on ferroelectric thin film switching reliability
APPLIED PHYSICS LETTERS
2007; 91 (23)
View details for DOI 10.1063/1.2822419
View details for Web of Science ID 000251450600074
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Metastability of Au-Ge liquid nanocatalysts: Ge vapor-liquid-solid nanowire growth far below the bulk eutectic temperature
ACS NANO
2007; 1 (5): 415-422
Abstract
The vapor-liquid-solid mechanism of nanowire (NW) growth requires the presence of a liquid at one end of the wire; however, Au-catalyzed Ge nanowire growth by chemical vapor deposition can occur at approximately 100 degrees C below the bulk Au-Ge eutectic. In this paper, we investigate deep sub-eutectic stability of liquid Au-Ge catalysts on Ge NWs quantitatively, both theoretically and experimentally. We construct a binary Au-Ge phase diagram that is valid at the nanoscale and show that equilibrium arguments, based on capillarity, are inconsistent with stabilization of Au-Ge liquid at deep sub-eutectic temperatures, similar to those used in Ge NW growth. Hot-stage electron microscopy and X-ray diffraction are used to test the predictions of nanoscale phase equilibria. In addition to Ge supersaturation of the Au-Ge liquid droplet, which has recently been invoked as an explanation for deep sub-eutectic Ge NW growth, we find evidence of a substantial kinetic barrier to Au solidification during cooling below the nanoscale Au-Ge eutectic temperature.
View details for DOI 10.1021/nn7001486
View details for Web of Science ID 000252022900011
View details for PubMedID 19206662
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Conditions for subeutectic growth of Ge nanowires by the vapor-liquid-solid mechanism
JOURNAL OF APPLIED PHYSICS
2007; 102 (9)
View details for DOI 10.1063/1.2803893
View details for Web of Science ID 000250983700084
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Lead zirconate titanate ferroelectric thin film capacitors: Effects of surface treatments on ferroelectric properties
APPLIED PHYSICS LETTERS
2007; 91 (7)
View details for DOI 10.1063/1.2769394
View details for Web of Science ID 000248866600083
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Vertically oriented germanium nanowires grown from gold colloids on silicon substrates and subsequent gold removal
NANO LETTERS
2007; 7 (6): 1637-1642
Abstract
A linker-free method to deposit citrate-stabilized Au colloids onto hydrogen-terminated Si by acidifying the Au colloid solution with HF or HCl is presented. This method prevents oxide formation and provides a model system for studying orientation control of nanowires by epitaxy. Conditions are reported that result in vertically oriented Ge nanowires of uniform diameter and length on Si(111). We then present a method to remove Au catalysts from the nanowires with aqueous triiodide and HCl.
View details for DOI 10.1021/nl070595x
View details for Web of Science ID 000247186800037
View details for PubMedID 17530912
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Effect of Y doping and composition-dependent elastic strain on the electrical properties of (Ba,Sr)TiO3 thin films deposited at 520 degrees C (vol 87, art no 192906, 2005)
APPLIED PHYSICS LETTERS
2007; 90 (19)
View details for DOI 10.1063/1.2735541
View details for Web of Science ID 000246413400108
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Relaxorlike dielectric behavior in Ba0.7Sr0.3TiO3 thin films
JOURNAL OF APPLIED PHYSICS
2007; 101 (6)
View details for DOI 10.1063/1.2511367
View details for Web of Science ID 000245317700177
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Fluorine incorporation at HfO2/SiO2 interfaces in high-k metal-oxide-semiconductor gate stacks: Local electronic structure
APPLIED PHYSICS LETTERS
2007; 90 (11)
View details for DOI 10.1063/1.2712785
View details for Web of Science ID 000244959200069
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Electrical properties of germanium/metal-oxide gate stacks with atomic layer deposition grown hafnium-dioxide and plasma-synthesized interface layers
APPLIED PHYSICS LETTERS
2007; 90 (11)
View details for DOI 10.1063/1.2472197
View details for Web of Science ID 000244959200070
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High temperature phase transformation of tantalum nitride films deposited by plasma enhanced atomic layer deposition for gate electrode applications
APPLIED PHYSICS LETTERS
2007; 90 (10)
View details for DOI 10.1063/1.2643085
View details for Web of Science ID 000244791700042
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Oxidation-enhanced interdiffusion in Si1-xGex/Si1-yGey superlattices
APPLIED PHYSICS LETTERS
2007; 90 (8)
View details for DOI 10.1063/1.2434162
View details for Web of Science ID 000244420600047
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First principles study of the HfO2/SiO2 interface: Application to high-k gate structures
JOURNAL OF APPLIED PHYSICS
2007; 101 (3)
View details for DOI 10.1063/1.2433696
View details for Web of Science ID 000244250100087
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ALD resist formed by vapor-deposited self-assembled monolayers
LANGMUIR
2007; 23 (3): 1160-1165
Abstract
A new process of applying molecular resists to block HfO2 and Pt atomic layer deposition has been investigated. Monolayer films are formed from octadecyltrichlorosilane (ODTS) or tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and water vapor on native silicon oxide surfaces and from 1-octadecene on hydrogen-passivated silicon surfaces through a low-pressure chemical vapor deposition process. X-ray photoelectron spectroscopy data indicates that surfaces blocked by these monolayer resists can prevent atomic layer deposition of both HfO2 and Pt successfully. Time-dependent studies show that the ODTS monolayers continue to improve in blocking ability for as long as 48 h of formation time, and infrared spectroscopy measurements confirm an evolution of packing order over these time scales.
View details for DOI 10.1021/la0606401
View details for Web of Science ID 000243684100033
View details for PubMedID 17241027
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Atomic layer deposition of Y2O3/ZrO2 nanolaminates - A route to ultrathin solid-state electrolyte membranes
ELECTROCHEMICAL AND SOLID STATE LETTERS
2007; 10 (10): B161-B165
View details for DOI 10.1149/1.2759606
View details for Web of Science ID 000248659800003
- Bulk and Interfacial Oxygen Defects in HfO2 Gate Dielectric Stacks: A Critical Assessment 2007
- Oxidation-Enhanced Interdiffusion in Si1-xGex Si1-yGey Superlattices Appl. Phys. Lett. 2007; 90: 082109-1-3
- Oxygen Transfer from Metal Gate to High-k Gate Dielectric Stack: Interface Structure & Property Changes 2007
- Metastability of Au−Ge Liquid Nanocatalysts: Ge Vapor–Liquid–Solid Nanowire Growth Far below the Bulk Eutectic Temperature ACS Nano 2007; 1: 415-22
- Atomic Layer Deposition of Y2O3/ZrO2 Nanolaminates: A Route to Ultrathin Solid-State Electrolyte Membranes Electrochem. Solid-State Lett. 2007; 10: B161-65
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Interface-engineered Ge (100) and (111), N- and P-FETs with high mobility
IEEE International Electron Devices Meeting
IEEE. 2007: 723–726
View details for Web of Science ID 000259347800165
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Resistive switching mechanism in ZnxCd1-xS nonvolatile memory devices
IEEE ELECTRON DEVICE LETTERS
2007; 28 (1): 14-16
View details for DOI 10.1109/LED.2006.887640
View details for Web of Science ID 000243280900006
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Chemical states and electrical properties of a high-k metal oxide/silicon interface with oxygen-gettering titanium-metal-overlayer
APPLIED PHYSICS LETTERS
2006; 89 (14)
View details for DOI 10.1063/1.2358834
View details for Web of Science ID 000241056900088
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Improvement in high-k (HfO2/SiO2) reliability by incorporation of fluorine
IEEE ELECTRON DEVICE LETTERS
2006; 27 (10): 821-823
View details for DOI 10.1109/LED.2006.882564
View details for Web of Science ID 000240925900010
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Effect of impurities on the fixed charge of nanoscale HfO2 films grown by atomic layer deposition
APPLIED PHYSICS LETTERS
2006; 89 (11)
View details for DOI 10.1063/1.2348735
View details for Web of Science ID 000240545400096
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Mechanism of germanium plasma nitridation
7th AVS International Conference on Microelectronics and Interfaces (ICMI06)
A V S AMER INST PHYSICS. 2006: 2442–48
View details for DOI 10.1116/1.2348887
View details for Web of Science ID 000241476500045
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Physical and electrical properties of plasma nitrided germanium oxynitride
7th AVS International Conference on Microelectronics and Interfaces (ICMI06)
A V S AMER INST PHYSICS. 2006: 2449–56
View details for DOI 10.1116/1.234886
View details for Web of Science ID 000241476500046
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High-efficiency metal-semiconductor-metal photodetectors on heteroepitaxially grown Ge on Si
OPTICS LETTERS
2006; 31 (17): 2565-2567
Abstract
We demonstrate extremely efficient germanium-on-silicon metal-semiconductor-metal photodetectors with responsivities (R) as high as 0.85 A/W at 1.55 microm and 2V reverse bias. Ge was directly grown on Si by using a novel heteroepitaxial growth technique, which uses multisteps of growth and hydrogen annealing to reduce surface roughness and threading dislocations that form due to the 4.2% lattice mismatch. Photodiodes on such layers exhibit reverse dark currents of 100 mA/cm2 and external quantum efficiency up to 68%. This technology is promising to realize monolithically integrated optoelectronics.
View details for Web of Science ID 000240008700017
View details for PubMedID 16902620
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Nature of germanium nanowire heteroepitaxy on silicon substrates
JOURNAL OF APPLIED PHYSICS
2006; 100 (2)
View details for DOI 10.1063/1.2219007
View details for Web of Science ID 000239423400124
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Nanoscale germanium MOS dielectrics - Part II: High-kappa gate dielectrics
IEEE TRANSACTIONS ON ELECTRON DEVICES
2006; 53 (7): 1509-1516
View details for DOI 10.1109/TED.2006.875812
View details for Web of Science ID 000238621600002
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Germanium nanowire epitaxy: Shape and orientation control
NANO LETTERS
2006; 6 (2): 318-323
Abstract
Epitaxial growth of nanowires along the 111 directions was obtained on Ge(111), Ge(110), Ge(001), and heteroepitaxial Ge on Si(001) substrates at temperatures of 350 degrees C or less by gold-nanoparticle-catalyzed chemical vapor deposition. On Ge(111), the growth was mostly vertical. In addition to 111 growth, 110 growth was observed on Ge(001) and Ge(110) substrates. Tapering was avoided by the use of the two-temperature growth procedure, reported earlier by Greytak et al.
View details for DOI 10.1021/nl052231f
View details for Web of Science ID 000235532700034
View details for PubMedID 16464057
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Atomic layer deposition of ultrathin metal-oxide films for nano-scale device applications
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
2006; 48 (1): 5-17
View details for Web of Science ID 000234660100002
- Strain Enhanced High Efficiency Germanium Photodetectors in the Near Infrared for Integration with Si 2006
- Nanoscale Germanium MOS Dielectrics - Part II: High-kapp Gate Dielectrics IEEE Trans. Electron Dev. 2006; 53: 1509-16
- Effects of Nitrogen Reactive Species on Germanium Plasma Nitridation Processes 2006
- Interface Layers for High-k/Ge Gate Stacks: Are They Necessary? 2006
- High Performance Barium Strontium Titanate Thin Film Capacitors for Decoupling Applications 2006
- Area Selective Atomic Layer Deposition by Soft Lithography 2006
- Chemical States and Electrical Properties of a High- k Metal Oxide/Silicon Interface with Oxygen-Gettering Titanium-Metal-Overlayer Appl. Phys. Lett. 2006; 89
- Structural Evolution and Point Defects in Metal Oxide-Based High-k Gate Dielectrics 2006
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Z-contrast and electron energy loss spectroscopy study of passive layer formation at ferroelectric PbTiO3/Pt interfaces
APPLIED PHYSICS LETTERS
2005; 87 (26)
View details for DOI 10.1063/1.2144279
View details for Web of Science ID 000234338700067
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Photoemission studies of passivation of germanium nanowires
APPLIED PHYSICS LETTERS
2005; 87 (26)
View details for DOI 10.1063/1.2158027
View details for Web of Science ID 000234338700081
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Effect of Y doping and composition-dependent elastic strain on the electrical properties of (Ba,Sr)TiO3 thin films deposited at 520 degrees C
APPLIED PHYSICS LETTERS
2005; 87 (19)
View details for DOI 10.1063/1.2125113
View details for Web of Science ID 000233058800053
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Comparative study on electrical and microstructural characteristics of ZrO2 and HfO2 grown by atomic layer deposition
JOURNAL OF MATERIALS RESEARCH
2005; 20 (11): 3125-3132
View details for DOI 10.1557/JMR.2005.0394
View details for Web of Science ID 000233095400032
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Self-assembled monolayers as resists for atomic layer deposition
230th National Meeting of the American-Chemical-Society
AMER CHEMICAL SOC. 2005: U1193–U1194
View details for Web of Science ID 000236797302400
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Passive Layer Formation at Pt/PbTiO3 Interfaces Identified Using STEM and EFTEM.
Microscopy and microanalysis
2005; 11: 1746-1747
Abstract
Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005.
View details for DOI 10.1017/S1431927605502198
View details for PubMedID 24017741
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Chemical states and electronic structure of a HfO2/Ge(001) interface
APPLIED PHYSICS LETTERS
2005; 87 (4)
View details for DOI 10.1063/1.2006211
View details for Web of Science ID 000230725900045
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Ge based high performance nanoscale MOSFETs
14th Biennial Conference on Insulating Films on Semiconductors
ELSEVIER SCIENCE BV. 2005: 15–21
View details for DOI 10.1016/j.mee.2005.04.038
View details for Web of Science ID 000231517000005
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Surface passivation and electronic structure characterization of PbTiO3 thin films and Pt/PbTiO3 interfaces
JOURNAL OF APPLIED PHYSICS
2005; 97 (10)
View details for DOI 10.1063/1.1897073
View details for Web of Science ID 000230168100109
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Achieving area-selective atomic layer deposition on patterned substrates by selective surface modification
APPLIED PHYSICS LETTERS
2005; 86 (19)
View details for DOI 10.1063/1.1922076
View details for Web of Science ID 000229397900026
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Structural, electronic, and dielectric properties of ultrathin zirconia films on silicon
APPLIED PHYSICS LETTERS
2005; 86 (15)
View details for DOI 10.1063/1.1864235
View details for Web of Science ID 000228901600076
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Formation of an interfacial Zr-silicate layer between ZrO2 and Si through in situ vacuum annealing
APPLIED PHYSICS LETTERS
2005; 86 (8)
View details for DOI 10.1063/1.1866644
View details for Web of Science ID 000227609000054
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Investigation of self-assembled monolayer resists for hafnium dioxide atomic layer deposition
CHEMISTRY OF MATERIALS
2005; 17 (3): 536-544
View details for DOI 10.1021/cm0486666
View details for Web of Science ID 000226804000011
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Misfit dislocation dissociation and Lomer formation in low mismatch SiGe/Si heterostructures
JOURNAL OF MATERIALS RESEARCH
2005; 20 (2): 447-455
View details for DOI 10.1557/JMR.2005.0065
View details for Web of Science ID 000229293000027
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O-18 tracer diffusion in Pb(Zr,Ti)O-3 thin films: A probe of local oxygen vacancy concentration
JOURNAL OF APPLIED PHYSICS
2005; 97 (2)
View details for DOI 10.1063/1.1814813
View details for Web of Science ID 000226700500022
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Influence of Ge concentration and compressive biaxial stress on interdiffusion in Si-rich SiGe alloy heterostructures
JOURNAL OF APPLIED PHYSICS
2005; 97 (1)
View details for DOI 10.1063/1.1828240
View details for Web of Science ID 000226700300039
- O18 Tracer Diffusion in Pb(Zr,Ti)O3 Thin Films: A Probe of Local Oxygen Vacancy Concentration J. Appl. Phys. 2005; 97: 023508-1
- Y-Doping Effects on the Dielectric Behavior of RF-Sputtered BST Thin Films 2005
- Effect of Y Doping and Composition-Dependent Elastic Strain on the Electrical Properties of (Ba,Sr)TiO3 Thin Films Deposited at 520°C Appl. Phys. Lett. 2005; 87: 1-3
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In situ low-angle x-ray scattering study of phase separation in initially mixed HfO2-SiO2 thin film interfaces
APPLIED PHYSICS LETTERS
2004; 85 (24): 5884-5886
View details for DOI 10.1063/1.1831554
View details for Web of Science ID 000225620200023
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Film and interface layer properties of ultraviolet-ozone oxidized hafnia and zirconia gate dielectrics on silicon substrates
APPLIED PHYSICS LETTERS
2004; 85 (20): 4699-4701
View details for DOI 10.1063/1.1814799
View details for Web of Science ID 000225166400047
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Interfacial characteristics of HfO2 grown on nitrided Ge (100) substrates by atomic-layer deposition
APPLIED PHYSICS LETTERS
2004; 85 (14): 2902-2904
View details for DOI 10.1063/1.1797564
View details for Web of Science ID 000224547300076
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Engineering chemically abrupt high-k metal oxide/silicon interfaces using an oxygen-gettering metal overlayer
JOURNAL OF APPLIED PHYSICS
2004; 96 (6): 3467-3472
View details for DOI 10.1063/1.1776636
View details for Web of Science ID 000223720000069
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Zirconia grown by ultraviolet ozone oxidation on germanium(100) substrates
JOURNAL OF APPLIED PHYSICS
2004; 96 (1): 813-819
View details for DOI 10.1063/1.1745118
View details for Web of Science ID 000222093300129
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Self-assembled monolayer resist for atomic layer deposition of HfO2 and ZrO2 high-kappa gate dielectrics
APPLIED PHYSICS LETTERS
2004; 84 (20): 4017-4019
View details for DOI 10.1063/1.1751211
View details for Web of Science ID 000221269800021
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Atomic layer deposition of high-kappa dielectric for germanium MOS applications-substrate surface preparation
IEEE ELECTRON DEVICE LETTERS
2004; 25 (5): 274-276
View details for DOI 10.1109/LED.2004.827285
View details for Web of Science ID 000221180900016
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Oxygen permeability of ferroelectric thin film top electrodes and its effect on detectable fatigue cycling-induced oxygen isotope motion
JOURNAL OF MATERIALS RESEARCH
2004; 19 (4): 1265-1272
View details for DOI 10.1557/JMR.2004.0164
View details for Web of Science ID 000222316400040
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Crystallization kinetics and microstructure-dependent leakage current behavior of ultrathin HfO2 dielectrics: In situ annealing studies
APPLIED PHYSICS LETTERS
2004; 84 (12): 2064-2066
View details for DOI 10.1063/1.1667621
View details for Web of Science ID 000220268500018
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Interfacial characteristics of HfO2 films grown on strained Si0.7Ge0.3 by atomic-layer deposition
APPLIED PHYSICS LETTERS
2004; 84 (7): 1171-1173
View details for DOI 10.1063/1.1647703
View details for Web of Science ID 000188880000048
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Microstructural evolution of ZrO2-HfO2 nanolaminate structures grown by atomic layer deposition
JOURNAL OF MATERIALS RESEARCH
2004; 19 (2): 643-650
View details for Web of Science ID 000222316200037
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Charge trapping studies on ultrathin ZrO2 and HfO2 high-k dielectrics grown by room temperature ultraviolet ozone oxidation
APPLIED PHYSICS LETTERS
2004; 84 (3): 389-391
View details for DOI 10.1063/1.1636532
View details for Web of Science ID 000188114300027
- Atomic Layer Deposition of High-k Dielectric for Germanium MOS Applications – Substrate IEEE Electron Dev. Lett. 2004; 25: 274-6
- Self-Assembled Monolayer Resist for Atomic Layer Deposition of HfO2 and ZrO2 High-k Gate Dielectrics Appl. Phys. Lett. 2004; 84: 4017-19
- Experimental Study of Biaxial and Uniaxial Strain Effects on Carrier Mobility in Bulk and Ultrathin-Body SOI MOSFETs 2004
- Critical Current Angle-Dependent Measurements of Thin (15 nm) Chemically-Derived YBa2Cu3O7-d Films in Fields to 5.5 T Physica C 2004; 235-240: 3069-70
- Crystallization Kinetics and Microstructure-Dependent Leakage Current Behavior of Ultrathin HfO2 Dielectrics: In Situ Annealing Studies Appl. Phys. Lett. 2004; 84: 2064-66
- Controlling Area-Selective Atomic Layer Deposition of HfO2 Dielectric by Self-Assembled Monolayers 2004
- Zirconia Grown by Ultraviolet Ozone Oxidation on Germanium (100) Substrates J. Appl. Phys. 2004; 96: 813-19
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Origin and implications of the observed rhombohedral phase in nominally tetragonal Pb(Zr0.35Ti0.65)O-3 thin films
JOURNAL OF APPLIED PHYSICS
2003; 94 (8): 5210-5219
View details for DOI 10.1063/1.1610773
View details for Web of Science ID 000185664300075
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Phase separation in hafnium silicates for alternative gate dielectrics - Influence on the unoccupied states
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2003; 150 (10): F173-F177
View details for DOI 10.1149/1.1604115
View details for Web of Science ID 000185639800045
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Local epitaxial growth of ZrO2 on Ge(100) substrates by atomic layer epitaxy
APPLIED PHYSICS LETTERS
2003; 83 (13): 2647-2649
View details for DOI 10.1063/1.1613031
View details for Web of Science ID 000185521400049
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Germanium nanowire field-effect transistors with SiO2 and high-kappa HfO2 gate dielectrics
APPLIED PHYSICS LETTERS
2003; 83 (12): 2432-2434
View details for DOI 10.1063/1.1611644
View details for Web of Science ID 000185333200044
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Point defect distributions and their electrical effects on (Ba,Sr)TiO3/Pt thin films
JOURNAL OF APPLIED PHYSICS
2003; 94 (3): 1926-1933
View details for DOI 10.1063/1.1590063
View details for Web of Science ID 000184400400094
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Analysis of x-ray diffraction as a probe of interdiffusion in Si/SiGe heterostructures
JOURNAL OF APPLIED PHYSICS
2003; 94 (3): 1557-1564
View details for DOI 10.1063/1.1589600
View details for Web of Science ID 000184400400042
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Effect of applied mechanical strain on the ferroelectric and dielectric properties of Pb(Zr0.35Ti0.65)O-3 thin films
JOURNAL OF APPLIED PHYSICS
2003; 93 (11): 9231-9236
View details for DOI 10.1063/1.1569431
View details for Web of Science ID 000183144300062
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Ultraviolet-ozone oxidation of metal films
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
2003; 150 (5): F110-F115
View details for DOI 10.1149/1.1566416
View details for Web of Science ID 000182184200052
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Atomic layer deposition of ZrO2 on W for metal-insulator-metal capacitor application
APPLIED PHYSICS LETTERS
2003; 82 (17): 2874-2876
View details for DOI 10.1063/1.1569985
View details for Web of Science ID 000182399700043
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Polarization recovery of fatigued Pb(Zr,Ti)O-3 thin films: Switching current studies
JOURNAL OF APPLIED PHYSICS
2003; 93 (3): 1743-1747
View details for DOI 10.1063/1.1536019
View details for Web of Science ID 000180630200065
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Effects of crystallization on the electrical properties of ultrathin HfO2 dielectrics grown by atomic layer deposition
APPLIED PHYSICS LETTERS
2003; 82 (1): 106-108
View details for DOI 10.1063/1.1533117
View details for Web of Science ID 000180134100036
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Structural analysis of coexisting tetragonal and rhombohedral phases in polycrystalline Pb(Zr0.35Ti0.65)O-3 thin films
JOURNAL OF MATERIALS RESEARCH
2003; 18 (1): 173-179
View details for Web of Science ID 000180363400024
- Polarization Recovery of Fatigued Pb(Zr,Ti)O3 Thin Films: Switching Current Studies J. Appl. Phys. 2003; 93: 1743-47
- Effect of Applied Mechanical Strain on the Ferroelectric and Dielectric Properties of Pb(Zr0.35Ti0.65)O3 Thin Films J. Appl. Phys. 2003; 93: 9231-36
- Structural Analysis of Coexisting Tetragonal and Rhombohedral Phases in Polycrystalline Pb(Zr0.35Ti 0.65)O3 Thin Films J. Mater. Res. 2003; 18: 173-9
- Local Epitaxial Growth of ZrO2 on Ge (100) Substrates by Atomic Layer Epitaxy Appl. Phys. Lett. 2003; 83: 2647-49
- Phase Separation in Hafnium Silicates for Alternative Gate Dielectrics: Influence on the Unoccupied States J. Electrochem. Soc. 2003; 150: F173-77
- Interdiffusion in Coherent Si0.70Ge0.30/Si0.95Ge0.05 Superlattices 2003
- A Germanium NMOSFET Process Integrating Metal Gate and Improved Hi-k Dielectrics 2003
- A Novel Self-Aligned Gate-Last MOSFET Process Comparing High-k Candidates 2003
- Germanium Nanowire Field-Effect Transistors with SiO2 and High-k HfO2 Gate Dielectrics Appl. Phys. Lett. 2003; 83: 2432-34
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High-kappa dielectrics for advanced carbon-nanotube transistors and logic gates
NATURE MATERIALS
2002; 1 (4): 241-246
Abstract
The integration of materials having a high dielectric constant (high-kappa) into carbon-nanotube transistors promises to push the performance limit for molecular electronics. Here, high-kappa (approximately 25) zirconium oxide thin-films (approximately 8 nm) are formed on top of individual single-walled carbon nanotubes by atomic-layer deposition and used as gate dielectrics for nanotube field-effect transistors. The p-type transistors exhibit subthreshold swings of S approximately 70 mV per decade, approaching the room-temperature theoretical limit for field-effect transistors. Key transistor performance parameters, transconductance and carrier mobility reach 6,000 S x m(-1) (12 microS per tube) and 3,000 cm2 x V(-1) x s(-1) respectively. N-type field-effect transistors obtained by annealing the devices in hydrogen exhibit S approximately 90 mV per decade. High voltage gains of up to 60 are obtained for complementary nanotube-based inverters. The atomic-layer deposition process affords gate insulators with high capacitance while being chemically benign to nanotubes, a key to the integration of advanced dielectrics into molecular electronics.
View details for DOI 10.1038/nmat769
View details for PubMedID 12618786
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Spinodal decomposition in amorphous metal-silicate thin films: Phase diagram analysis and interface effects on kinetics
JOURNAL OF APPLIED PHYSICS
2002; 92 (9): 5094-5102
View details for DOI 10.1063/1.1510590
View details for Web of Science ID 000178767200035
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Observation and modeling of the initial fast interdiffusion regime in Si/SiGe multilayers
JOURNAL OF APPLIED PHYSICS
2002; 92 (9): 5027-5035
View details for DOI 10.1063/1.1508424
View details for Web of Science ID 000178767200026
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Oxygen tracer studies of ferroelectric fatigue in Pb(Zr,Ti)O-3 thin films
APPLIED PHYSICS LETTERS
2002; 81 (17): 3218-3220
View details for DOI 10.1063/1.1516628
View details for Web of Science ID 000178624900034
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Effects of long-time DC bias on D2O- and D-2/N-2-annealed BST thin films
JOURNAL OF ELECTROCERAMICS
2002; 9 (1): 25-30
View details for Web of Science ID 000179916000003
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Structural studies of ultrathin zirconia dielectrics
PHILOSOPHICAL MAGAZINE LETTERS
2002; 82 (9): 519-528
View details for DOI 10.1080/09500830210157108
View details for Web of Science ID 000177786400007
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Thermal stability of polycrystalline silicon electrodes on ZrO2 gate dielectrics
APPLIED PHYSICS LETTERS
2002; 81 (8): 1417-1419
View details for DOI 10.1063/1.1499513
View details for Web of Science ID 000177351600017
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Germanium MOS capacitors incorporating ultrathin high-kappa gate dielectric
IEEE ELECTRON DEVICE LETTERS
2002; 23 (8): 473-475
View details for DOI 10.1009/LED.2002.801319
View details for Web of Science ID 000177207300010
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Ultrathin zirconia/SiO2 dielectric stacks grown by ultraviolet-ozone oxidation
APPLIED PHYSICS LETTERS
2002; 80 (20): 3793-3795
View details for DOI 10.1063/1.1481241
View details for Web of Science ID 000175564100043
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Electrical properties of thin film zirconia grown by ultraviolet ozone oxidation
JOURNAL OF APPLIED PHYSICS
2002; 91 (7): 4521-4527
View details for DOI 10.1063/1.1459103
View details for Web of Science ID 000174663900087
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Thickness-dependent phase evolution of polycrystalline Pb(Zr0.35Ti0.65)O-3 thin films
APPLIED PHYSICS LETTERS
2002; 80 (7): 1258-1260
View details for DOI 10.1063/1.1449532
View details for Web of Science ID 000173896400050
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Effect of oxygen stoichiometry on the electrical properties of zirconia gate dielectrics
APPLIED PHYSICS LETTERS
2001; 79 (20): 3311-3313
View details for Web of Science ID 000172046800033
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Growth and characterization of ultrathin zirconia dielectrics grown by ultraviolet ozone oxidation
APPLIED PHYSICS LETTERS
2001; 79 (16): 2621-2623
View details for Web of Science ID 000171466200040
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Microstructural study of epitaxial platinum and permalloy/platinum films grown on (0001) sapphire
PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES
2001; 81 (8): 2073-2094
View details for Web of Science ID 000170354500013
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Point defect equilibrium in strontium titanate thin films
JOURNAL OF APPLIED PHYSICS
2001; 89 (12): 8074-8084
View details for Web of Science ID 000169183500063
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Deuterium in (Ba,Sr)TiO3 thin films: Kinetics and mechanisms of incorporation and removal during annealing
JOURNAL OF APPLIED PHYSICS
2001; 89 (11): 6378-6388
View details for Web of Science ID 000169149900080
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Electrical and materials properties of ZrO2 gate dielectrics grown by atomic layer chemical vapor deposition
APPLIED PHYSICS LETTERS
2001; 78 (16): 2357-2359
View details for Web of Science ID 000168275200031
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Dielectric relaxation and steady-state leakage in low-temperature sputtered (Ba, Sr)TiO3 thin films
JOURNAL OF APPLIED PHYSICS
2001; 89 (4): 2309-2313
View details for Web of Science ID 000166688300049
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Deuterium-induced degradation of (Ba, Sr)TiO3 films
APPLIED PHYSICS LETTERS
2000; 77 (9): 1378-1380
View details for Web of Science ID 000088900900047
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Equilibrium point defect and electronic carrier distributions near interfaces in acceptor-doped strontium titanate
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
2000; 83 (5): 1129-1136
View details for Web of Science ID 000087329000020
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The properties of ferroelectric films at small dimensions
ANNUAL REVIEW OF MATERIALS SCIENCE
2000; 30: 263-298
View details for Web of Science ID 000089332400011
- Deuterium-Induced Degradation of (Ba,Sr)TiO3 Thin Films Appl. Phys. Lett. 2000; 77: 1378-80
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Interpretation of ion channeling results from epitaxial Pt thin films and Co/Pt multilayers
13th International Conference on Ion Beam Analysis (IBA-13)
ELSEVIER SCIENCE BV. 1998: 214–219
View details for Web of Science ID 000074380400036
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Kinetics and mechanisms of TiN oxidation beneath Pt thin films
JOURNAL OF APPLIED PHYSICS
1997; 82 (9): 4577-4585
View details for Web of Science ID A1997YE45800075
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Oxidation kinetics of TiN layers: Exposed and beneath Pt thin films
APPLIED PHYSICS LETTERS
1997; 70 (6): 711-713
View details for Web of Science ID A1997WG82700013
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Epitaxy of Pt thin films on (001)MgO .2. Orientation evolution from nucleation through coalescence
ACTA MATERIALIA
1997; 45 (2): 879-887
View details for Web of Science ID A1997WF44300042
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Epitaxy of Pt thin films on (001)MgO .1. Interface energetics and misfit accommodation
ACTA MATERIALIA
1997; 45 (2): 869-878
View details for Web of Science ID A1997WF44300041
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The effects of forming gas anneal on the electrical characteristics of Ir-electroded BST thin film capacitors
9th International Symposium on Integrated Ferroelectrics
TAYLOR & FRANCIS LTD. 1997: 461–69
View details for Web of Science ID A1997YF22200046
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Resistance degradation of CVD (Ba,Sr)TiO3 thin films for drams and integrated decoupling capacitors
10th IEEE International Symposium on Applications of Ferroelectrics (ISAF 96)
IEEE. 1996: 51–54
View details for Web of Science ID A1996BH95D00009
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Ir-electroded BST thin film capacitors for 1 giga-bit DRAM application
1996 International Electron Devices Meeting
IEEE. 1996: 679–682
View details for Web of Science ID A1996BG98F00151
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Leakage currents in CVD (Ba,Sr)TiO3 thin films
Symposium on Ferroelectric Thin Films, at the 1996 MRS Spring Meeting
MATERIALS RESEARCH SOC. 1996: 285–290
View details for Web of Science ID A1996BG75Z00041
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ORIENTATION SELECTION IN THIN PLATINUM FILMS ON (001) MGO
JOURNAL OF APPLIED PHYSICS
1995; 77 (12): 6201-6204
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Crystallization kinetics of Fe-doped Al2O3
Symposium on Structure and Properties of Interfaces in Ceramics, at the 1994 Fall Meeting of the Materials-Research-Society
MATERIALS RESEARCH SOC. 1995: 201–205
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