Fabrication of high-photoresponsivity BaSi 2 films by sputtering and photogenerated carrier separation in BaSi 2 /n + -Si heterojunction diodes with n + -Si as electron transport layers

作者：Takumi Sato, Md Ariful Islam, Koki Hayashi, Yuka Fukaya, Rui Du, Mizuki Hirai, Yoichiro Koda, Masami Mesuda, Kaoru Toko, Takashi Suemasu · 发表于：Japanese Journal of Applied Physics · 年份：2025 · DOI：10.35848/1347-4065/ae2588 · 被引用次数：2 · 研究领域：Semiconductor materials and interfaces、Silicon and Solar Cell Technologies、Chemical and Physical Properties of Materials

Abstract BaSi 2 is a promising material for thin-film solar cell applications. In this paper, the effect of the deposition rate ratio of BaSi 2 to Ba targets ( R BaSi2 / R Ba ) is investigated using photoresponsivity as a measure for BaSi 2 films deposited by co-sputtering. Photoresponsivity is highly dependent on R BaSi2 / R Ba , and at R BaSi2 / R Ba = 5.8, the electron mobility reaches 1700 cm 2 V −1 s −1 and the photoresponsivity is the highest ever reported for BaSi 2 films. Under AM1.5G illumination, the rectifying current-density versus voltage characteristics of the n-BaSi 2 /n + -Si diode is distinctly observed, and that the external quantum efficiency (EQE) begins to increase at a wavelength of approximately 950 nm. Similar EQE spectra were obtained for BaSi 2 films formed on n + -Si/W/glass, demonstrating the separation of photogenerated carriers in BaSi 2 films even on glass substrates. This fact indicates that BaSi 2 functions as the light-absorbing layer and further demonstrates that the n + -Si acts as the electron transport layer.