Band gap opening at the 6H-SiC(0001) surface passivated by an epitaxial silicon oxynitride layer: A first-principles investigation

被引：6

作者：

Devynck, Fabien ^{[1
]}

Pasquarello, Alfredo

机构：

[1] Ecole Polytech Fed Lausanne, Inst Theoret Phys, CH-1015 Lausanne, Switzerland

来源：

SURFACE SCIENCE | 2008年 / 602卷 / 18期

基金：

瑞士国家科学基金会;

关键词：

Band gap; Electronic structure; Epitaxial structure; Interface structure;

D O I：

10.1016/j.susc.2008.07.036

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Using hybrid density functionals, we investigate the origin of the large band gap experimentally observed at the 6H-SiC(0001) surface when passivated by an epitaxial silicon oxynitride layer. In order to distinguish the effects resulting from the interfacial nitrogen layer and from the thinness of the epitaxial oxide layer, we use various models of the 6H-SiC(0001)/SiO2 interface and perform a comparative study through the evolutions of their planar-averaged local density of states across the interface. Our study attributes the large band gap opening to a combined effect. The presence of the nitrogen layer causes the band gap to open already in the last planes of the substrate. The thinness of the epitaxial layer contributes to a further increase of the band gap in the close vicinity of the outer surface and its effect is enhanced by the presence of the nitrogen layer. (C) 2008 Elsevier B.V. All rights reserved.

引用

页码：2989 / 2993

页数：5

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