title: Towards direct-gap silicon phases by the inverse band structure design approach.
abstract: Diamond silicon (Si) is the leading material in the current solar cell market. However, diamond Si is an indirect band gap semiconductor with a large energy difference (2.3 eV) between the direct gap and the indirect gap, which makes it an inefficient absorber of light. In this work, we develop a novel inverse band structure design approach based on the particle swarming optimization algorithm to predict the metastable Si phases with better optical properties than diamond Si. Using our new method, we predict a cubic Si(20) phase with quasidirect gaps of 1.55 eV, which is a promising candidate for making thin-film solar cells.
authors.affiliation: Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China and National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Xiang
authors.affiliation: National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Huang
authors.affiliation: Department of Applied Physics, Nanjing University of Science and Technology, Nanjing, Jiangsu 210094, People's Republic of China.
authors.forename: Erjun
authors.initials: E
authors.lastname: Kan
authors.affiliation: National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
authors.forename: Su-Huai
authors.initials: SH
authors.lastname: Wei
authors.affiliation: Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, People's Republic of China.
authors.forename: X G
authors.initials: XG
authors.lastname: Gong