title: Si3AlP: a new promising material for solar cell absorber.
abstract: First-principles calculations were performed to study the structural and optoelectronic properties of the newly synthesized nonisovalent and lattice-matched (Si(2))(0.6)(AlP)(0.4) alloy (Watkins, T.; et al. J. Am. Chem. Soc.2011, 133, 16212). We found that the most stable structure of Si(3)AlP is a superlattice along the [111] direction with separated AlP and Si layers, which has a similar optical absorption spectrum to silicon. The ordered C1c1-Si(3)AlP is found to be the most stable one among all structures with a basic unit of one P atom surrounded by three Si atoms and one Al atom, in agreement with experimental suggestions. We predict that C1c1-Si(3)AlP has good optical properties, i.e., it has a larger fundamental band gap and a smaller direct band gap than Si; thus, it has much higher absorption in the visible light region. The calculated properties of Si(3)AlP suggest that it is a promising candidate for improving the performance of the existing Si-based solar cells. The understanding on the stability and band structure engineering obtained in this study is general and can be applied for future study of other nonisovalent and lattice-matched semiconductor alloys.
authors: Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, P R China.
authors: Ji-Hui
authors: JH
authors: Yang
authors: Yingteng
authors: Y
authors: Zhai
authors: Hengrui
authors: H
authors: Liu
authors: Hongjun
authors: H
authors: Xiang
authors: Xingao
authors: X
authors: Gong
authors: Su-Huai
authors: SH
authors: Wei