Impact of Al2O3 Passivation on the Photovoltaic Performance of Vertical WSe2 Schottky Junction Solar Cells
Author(s)
McVay, Elaine D.; Zubair, Ahmad; Lin, Yuxuan; Nourbakhsh, Amirhasan; Palacios, Tomas
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Transition metal dichalcogenide (TMD) materials have emerged as promising candidates for thin-film solar cells due to their wide bandgap range across the visible wavelengths, high absorption coefficient, and ease of integration with both arbitrary substrates and conventional semiconductor technologies. However, reported TMD-based solar cells suffer from relatively low external quantum efficiencies (EQE) and low open circuit voltage due to unoptimized design and device fabrication. This paper studies Pt/WSe₂ vertical Schottky junction solar cells with various WSe₂ thicknesses in order to find the optimum absorber thickness. Also, we show that the devices' photovoltaic performance can be improved via Al₂O₃ passivation, which increases the EQE up to 29.5% at 410 nm wavelength incident light. The overall resulting short circuit current improves through antireflection coating, surface doping, and surface trap passivation effects. Thanks to the Al₂O₃ coating, this work demonstrates a device with an open circuit voltage (VOC) of 380 mV and a short circuit current density (JSC) of 10.7 mA/cm². Finally, the impact of Schottky barrier height inhomogeneity at the Pt/WSe2 contact is investigated as a source of open circuit voltage lowering in these devices.
Date issued
2020-12Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer ScienceJournal
ACS Applied Materials and Interfaces
Publisher
American Chemical Society (ACS)
Citation
McVay, Elaine et al. "Impact of Al2O3 Passivation on the Photovoltaic Performance of Vertical WSe2 Schottky Junction Solar Cells." ACS Applied Materials and Interfaces 12, 52 (December 2020): 57987–57995 © 2020 American Chemical Society
Version: Author's final manuscript
ISSN
1944-8244
1944-8252