title: Direct band gap silicon allotropes.
abstract: Elemental silicon has a large impact on the economy of the modern world and is of fundamental importance in the technological field, particularly in solar cell industry. The great demand of society for new clean energy and the shortcomings of the current silicon solar cells are calling for new materials that can make full use of the solar power. In this paper, six metastable allotropes of silicon with direct or quasidirect band gaps of 0.39-1.25 eV are predicted by ab initio calculations at ambient pressure. Five of them possess band gaps within the optimal range for high converting efficiency from solar energy to electric power and also have better optical properties than the Si-I phase. These Si structures with different band gaps could be applied to multiple p-n junction photovoltaic modules.
authors: State Key Laboratory of Metastable Materials Science and Technology, Yanshan University , Qinhuangdao 066004, Hebei Province, China.
authors: Qianqian
authors: Q
authors: Wang
authors: Bo
authors: B
authors: Xu
authors: Jian
authors: J
authors: Sun
authors: Hanyu
authors: H
authors: Liu
authors: Zhisheng
authors: Z
authors: Zhao
authors: Dongli
authors: D
authors: Yu
authors: Changzeng
authors: C
authors: Fan
authors: Julong
authors: J
authors: He