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All Publications

  • High-Performance p-n Junction Transition Metal Dichalcogenide Photovoltaic Cells Enabled by MoOx Doping and Passivation. Nano letters Nassiri Nazif, K., Kumar, A., Hong, J., Lee, N., Islam, R., McClellan, C. J., Karni, O., van de Groep, J., Heinz, T. F., Pop, E., Brongersma, M. L., Saraswat, K. C. 2021


    Layered semiconducting transition metal dichalcogenides (TMDs) are promising materials for high-specific-power photovoltaics due to their excellent optoelectronic properties. However, in practice, contacts to TMDs have poor charge carrier selectivity, while imperfect surfaces cause recombination, leading to a low open-circuit voltage (VOC) and therefore limited power conversion efficiency (PCE) in TMD photovoltaics. Here, we simultaneously address these fundamental issues with a simple MoOx (x 3) surface charge-transfer doping and passivation method, applying it to multilayer tungsten disulfide (WS2) Schottky-junction solar cells with initially near-zero VOC. Doping and passivation turn these into lateral p-n junction photovoltaic cells with a record VOC of 681 mV under AM 1.5G illumination, the highest among all p-n junction TMD solar cells with a practical design. The enhanced VOC also leads to record PCE in ultrathin (<90 nm) WS2 photovoltaics. This easily scalable doping and passivation scheme is expected to enable further advances in TMD electronics and optoelectronics.

    View details for DOI 10.1021/acs.nanolett.1c00015

    View details for PubMedID 33852295

  • Doped WS2 transistors with large on-off ratio and high on-current Kumar, A., Nazif, K., Ramesh, P., Saraswat, K., IEEE IEEE. 2020
  • On the limit of defect doping in transition metal oxides JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A Kumar, A., Islam, R., Pramanik, D., Saraswat, K. 2019; 37 (2)

    View details for DOI 10.1116/1.5055563

    View details for Web of Science ID 000460437200050

  • Towards high V-oc, thin film, homojunction WS2 solar cells for energy harvesting applications Nazif, K., Kumar, A., de Menezes, M., Saraswat, K., Matin, M., Lange, A. P., Dutta, A. K. SPIE-INT SOC OPTICAL ENGINEERING. 2019

    View details for DOI 10.1117/12.2533007

    View details for Web of Science ID 000511164400001