1211.0591 (H. J. Xiang et al.)

Towards Direct-Gap Silicon Phases by the Inverse Band Structure Design
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H. J. Xiang, Bing Huang, Erjun Kan, Su-Huai Wei, X. G. Gong

Diamond silicon (Si) is the leading material in current solar cell market. However, diamond Si is an indirect band gap semiconductor with a large energy difference (2.4 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 Si20 phase with quasi-direct gaps of 1.55 eV, which is a promising candidate for making thin-film solar cells.

View original: http://arxiv.org/abs/1211.0591