材料科学
各向异性
凝聚态物理
半导体
图层(电子)
吸光度
带隙
光电子学
纳米技术
光学
物理
作者
Guangsha Shi,Emmanouil Kioupakis
出处
期刊:Nano Letters
[American Chemical Society]
日期:2015-09-22
卷期号:15 (10): 6926-6931
被引量:320
标识
DOI:10.1021/acs.nanolett.5b02861
摘要
SnSe and GeSe are layered compound semiconductors that can be exfoliated to form two-dimensional materials. In this work, we use predictive calculations based on density functional and many-body perturbation theory to study the electronic and optical properties of single-layer, double-layer, and bulk SnSe and GeSe. The fundamental band gap is direct in single-layer and double-layer GeSe, but indirect in single-layer and double-layer SnSe. Moreover, the interplay of spin–orbit coupling and lack of inversion symmetry in the monolayer structures results in anisotropic spin splitting of the energy bands, with potential applications in directionally dependent spin transport. We also show that single-layer and double-layer SnSe and GeSe exhibit unusually strong optical absorbance in the visible range. Our results suggest that single-layer and double-layer SnSe and GeSe are promising materials for ultrathin-film photovoltaic applications with theoretical upper bounds to the conversion efficiency that approach the efficiency records realized in organic and dye-sensitized solar cells.
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