McVay Elaine, Zubair Ahmad, Lin Yuxuan, Nourbakhsh Amirhasan, Palacios Tomás
Department of Electrical Engineering Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
ACS Appl Mater Interfaces. 2020 Dec 30;12(52):57987-57995. doi: 10.1021/acsami.0c15573. Epub 2020 Dec 15.
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/WSe vertical Schottky junction solar cells with various WSe thicknesses in order to find the optimum absorber thickness. Also, we show that the devices' photovoltaic performance can be improved via AlO 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 AlO coating, this work demonstrates a device with an open circuit voltage () of 380 mV and a short circuit current density () of 10.7 mA/cm. Finally, the impact of Schottky barrier height inhomogeneity at the Pt/WSe contact is investigated as a source of open circuit voltage lowering in these devices.
过渡金属二硫属化物（TMD）材料因其在可见波长范围内具有较宽的带隙、高吸收系数以及易于与任意衬底和传统半导体技术集成，已成为薄膜太阳能电池的有前景的候选材料。然而，由于设计和器件制造未优化，报道的基于TMD的太阳能电池的外量子效率（EQE）相对较低且开路电压较低。本文研究了具有不同WSe厚度的Pt/WSe垂直肖特基结太阳能电池，以找到最佳吸收体厚度。此外，我们表明通过AlO钝化可以提高器件的光伏性能，在410nm波长入射光下，EQE可提高至29.5%。通过减反射涂层、表面掺杂和表面陷阱钝化效应，整体短路电流得到改善。得益于AlO涂层，这项工作展示了一种开路电压（）为380mV、短路电流密度（）为10.7mA/cm²的器件。最后，研究了Pt/WSe接触处肖特基势垒高度不均匀性对这些器件开路电压降低的影响。
