title: Electronic and optical properties of silicon based porous sheets.
abstract: Si based sheets have attracted tremendous attention due to their compatibility with the well-developed Si-based semiconductor industry. On the basis of state-of-the-art theoretical calculations, we systematically study the stability, electronic and optical properties of Si based porous sheets including g-Si4N3, g-Si3N4, g-Si3N3 and g-Si3P3. We find that the g-Si3N3 and g-Si3P3 sheets are thermally stable, while the g-Si4N3 and g-Si3N4 are unstable. Different from the silicene-like sheets of SiN and Si3N which are nonplanar and metallic, both the porous g-Si3N3 and g-Si3P3 sheets are planar and nonmetallic, and the former is an indirect band gap semiconductor with a band gap of 3.50 eV, while the latter is a direct band gap semiconductor with a gap of 1.93 eV. Analysis of the optical absorption spectrum reveals that the g-Si3P3 sheet may have applications in solar absorbers owing to its narrow direct band gap and wide range optical absorption in the visible light spectrum.
authors.affiliation: HEDPS, Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871, China. qianwang2@pku.edu.cn.
authors.forename: Yaguang
authors.initials: Y
authors.lastname: Guo
authors.forename: Shunhong
authors.initials: S
authors.lastname: Zhang
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang