"GaAs thin film nanostructure arrays for III-V solar cell applications"

Dong Liang: Yangsen Kang, Yijie Huo, Ken Xinze Wang, Anjia Gu, Meiyueh Tan, Zongfu Yu, Shuang Li, Jieyang Jia, Xinyu Bao, Shuang Wang, Yan Yao, Shanhui Fan, Yi Cui, James Harris; SPIE Proceedings, 01/21/12.

Additional Authors: Yangsen Kang, Yijie Huo, Ken Xinze Wang, Anjia Gu, Meiyueh Tan, Zongfu Yu, Shuang Li, Jieyang Jia, Xinyu Bao, Shuang Wang, Yan Yao, Shanhui Fan, Yi Cui, James Harris

Abstract:

State of art III-V multi-junction solar cells have demonstrated a record high efficiency of 43.5%. However, these cells are only applicable to high concentration systems due to their high cost of substrates and epitaxial growth. We demonstrate thin film flexible nanostructure arrays for III-V solar cell applications. Such nanostructure arrays allow substrate recycling and much thinner epitaxial layer thus could significantly reduce the cost of traditional III-V solar cells. We fabricate the GaAs thin film nanostructure arrays by conformally growing GaAs thin film on nanostructured template followed by epitaxial lift-off. We demonstrate broadband optical absorption enhancement of a film of GaAs nanostructure arrays over a planar thin film with equal thickness. The absorption enhancement is about 300% at long wavelengths due to significant light trapping effect and about 30% at short wavelengths due to antireflection effect from tapered geometry. Optical simulation shows the physical mechanisms of the absorption enhancement. Using thin film nanostructure arrays, the III-V solar system cost could be greatly reduced, leading to low $/W and high kW/kg flexible solar systems.