Large-Scale Simulations of a-Si:H: The Origin of Midgap States Revisited

被引：30
作者：
Khomyakov, P. A. [1 ]
Andreoni, Wanda [1 ,2 ,3 ]
Afify, N. D. [1 ,4 ]
Curioni, Alessandro [1 ]
机构：
[1] IBM Res Zurich, Rschlikon, Switzerland
[2] Ecole Polytech Fed Lausanne, CECAM, CH-1015 Lausanne, Switzerland
[3] Ecole Polytech Fed Lausanne, Inst Theoret Phys, CH-1015 Lausanne, Switzerland
[4] Egypt IBM Nanotechnol Ctr, Giza, Egypt
来源：
PHYSICAL REVIEW LETTERS | 2011年 / 107卷 / 25期
关键词：
HYDROGENATED AMORPHOUS-SILICON; GENERALIZED GRADIENT APPROXIMATION; DEFECTS; GENERATION;
D O I：
10.1103/PhysRevLett.107.255502
中图分类号：
O4 [物理学];
学科分类号：
0702 ;
摘要：
Large-scale classical and quantum simulations are used to generate a-Si: H structures. The bond-resolved density of the occupied electron states discloses the nature of microscopic defects responsible for levels in the gap. Highly strained bonds give rise to band tails and midgap states. The latter originate mainly from stretched bonds, in addition to dangling bonds, and can act as hole traps. This study provides strong evidence for photoinduced degradation (Staebler-Wronski effect) driven by strain, thus supporting recent work on a-Si, and sheds light on the role of hydrogen.
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页数：4
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