Ashildur Fridriksdottir

All Publications

• Scaling nanoribbon transistors with monolayer transition metal dichalcogenides. Nature nanotechnology Peña, T., Persson, A. E., Krayev, A., Friðriksdóttir, Á., Su, H., Lee, Y. M., Song, Y. S., Neilson, K., Zhang, Z., Hoang, A. T., Yang, J. A., Hoang, L., Wang, S. X., Mannix, A. J., McIntyre, P. C., Pop, E. 2026

  Abstract

  Nanoscale transistors demand aggressive scaling of all channel dimensions-length, width and thickness. Two-dimensional semiconductors (2DS) provide the ultimate thickness limit, yet good device performance has largely remained restricted to micrometre-wide channels. Here we report monolayer 2DS nanoribbon transistors with both n- and p-type operation, fabricated by a top-down multipatterning process that includes 'anchored' contacts to limit nanoribbon delamination. This approach achieves channel lengths and widths down to 25-30 nm, with minimal edge degradation confirmed through nanoscale characterization, including tip-enhanced photoluminescence. Integrated with thin high-κ gate dielectrics, the devices deliver on-state currents up to 560, 420 and 130 µA µm-1 at a drain-to-source voltage of 1 V for n-type MoS2, n-type WS2 and p-type WSe2, respectively. These results exceed prior single-gated 2DS nanoribbon reports, with WS2 improving by more than two orders of magnitude, even for normally off (enhancement-mode) operation. Overall, these findings position top-down patterned 2DS nanoribbons as promising building blocks for future nanosheet transistor architectures.

  View details for DOI 10.1038/s41565-026-02161-w

  View details for PubMedID 42230814

  View details for PubMedCentralID 10570266

• Composition dependence of atomic order in strain-relaxed, metastable GeSn alloys PHYSICAL REVIEW MATERIALS Lentz, J., Fridriksdottir, A., Woicik, J. C., Davis, R., Mehta, A., Mcintyre, P. C. 2025; 9 (10)

  View details for DOI 10.1103/dyr8-q1g1

  View details for Web of Science ID 001592702700001

• Electrochemical Investigation of Enzyme Kinetics with an Unmediated, Unmodified Platinum Microelectrode: The Case of Glucose Oxidase. ACS electrochemistry Davis, C., Fridriksdottir, A., Alkhairi, O., Sepunaru, L. 2025

  Abstract

  We present a simple analytical method for studying the physical parameters governing redox-active enzyme kinetics using microscale electrodes. With the enzyme freely diffusing in solution, the interaction with its natural substrates produces a linearly increasing current corresponding to the reaction rate and the intrinsic thermodynamic properties of the enzyme. We show that external complications, such as artificial mediators or enzyme surface immobilization, can be avoided by using an unmediated, unmodified platinum microelectrode and that control over the dominating kinetic process can be readily achieved by changing the enzyme and (co)substrate concentrations. This is achieved using the glucose oxidase (GOx)/glucose system to compare with standard practice UV-Vis techniques, including the pH dependence of the enzyme activity. We illustrate how this straightforward chronoamperometric measurement is influenced by changes to reaction conditions commonly employed in enzyme investigations, including enzyme and oxygen concentrations as well as pH and the presence of chloride. Our method emphasizes that interpreting a simple increasing slope to analyze enzyme behavior requires ensuring adherence to initial rate assumptions, empirical observation of the current-concentration relationship, and insight from using the ping-pong framework. This enables a discussion of the bounds for evoking the commonly used Michaelis-Menten rate framework as well as the existing constraints of spectroscopy, contrasted with microscale voltammetry.

  View details for DOI 10.1021/acselectrochem.5c00139

  View details for PubMedID 40740411

  View details for PubMedCentralID PMC12306184