关于氧化硅烯结构和电子性质的第一性原理研究

利用基于广义梯度近似的密度泛函理论,本文研究了二维氧化硅烯的几何结构和电子特性.结果显示,随着氧含量的增加,氧原子更加倾向于以-（Si2O2）x-键的形式排列在硅烯表面.每一个-（Si2O2）x-键都会使临近氧原子的六个硅原子处在同一表面,并且四个Si-O键构成一个与之相垂直的平面.当所有的硅原子都转化成sp3杂化后,氧化硅烯会形成最稳定的全氧化结构并具有0.46 eV的带宽.部分氧化的硅烯结构具有从0.30 eV到0.38 eV的较小带宽,这些较小的带宽非常吻合较早时的关于氧化硅纳米带的带宽的实验数值（0.35 eV）,并且说明离子化的Si-O键和共价性的Si-Si键共存导致了较小带宽的出现.

The Structural and Electronic Properties of Silicene Oxide：A First-Principles Study

Using density functional theory with the generalized gradient approximation, the structural and electronic properties of a two-dimensional oxidized silicene are investigated. Our results show that oxygen atoms prefer to form the ordered arrangement of-（Si2O2）x- bonds in silicene with the increase of oxygen content. Each-（Si2O2）- bond makes six neighbor silicon atoms of the two oxygen atoms in a plane and its four Si-O bonds constitute a square vertical to this plane. When all silicon atoms are transferred to sp3 hybridization with the increase of the oxygen content, the fully oxidized structure（x=0.50） is the most stable structure with a calculated band gap of 0.46 eV. The small band gaps（from0.30 eV to 0.38 eV） of partly oxidized silicene（from x=0.06 to x=0.33） are consistent with the study of oxidized Si nanoribbons（its band gap is 0.35 eV） and the band gap is originated from the coexistence of these ionic Si-O bonds and covalent Si-Si bonds.