Efficiency Enhancement of Nanotextured Black Silicon Solar Cells Using Al2O3/TiO2 Dual-Layer Passivation Stack Prepared by Atomic Layer Deposition.
In this study, efficient nanotextured black silicon (NBSi) solar cells composed of silicon nanowire arrays and an Al2O3/TiO2 dual-layer passivation stack on the n(+) emitter were fabricated. The highly conformal Al2O3 and TiO2 surface passivation layers were deposited on the high-aspect-ratio surface of the NBSi wafers using atomic layer deposition. Instead of the single Al2O3 passivation layer with a negative oxide charge density, the Al2O3/TiO2 dual-layer passivation stack treated with forming gas annealing provides a high positive oxide charge density and a low interfacial state density, which are essential for the effective field-effect and chemical passivation of the n(+) emitter. In addition, the Al2O3/TiO2 dual-layer passivation stack suppresses the total reflectance over a broad range of wavelengths (400-1000 nm). Therefore, with the Al2O3/TiO2 dual-layer passivation stack, the short-circuit current density and efficiency of the NBSi solar cell were increased by 11% and 20%, respectively. In conclusion, a high efficiency of 18.5% was achieved with the NBSi solar cells by using the n(+)-emitter/p-base structure passivated with the Al2O3/TiO2 stack.
†Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan.
Wei-Cheng
WC
Wang
†Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan.
Meng-Chen
MC
Tsai
‡Sino-American Silicon Products Inc., Yilan Branch, Yilan County 26841, Taiwan.
Jason
J
Yang
§Sino-American Silicon Products Inc., Hsinchu Science Park 30075, Taiwan.
Chuck
C
Hsu
†Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan.
Miin-Jang
MJ
Chen
aluminum oxide (Al2O3); atomic layer deposition; nanotextured black silicon; silicon nanowire; solar cell; surface passivation; titanium dioxide (TiO2)