硅醚/石墨醚异质结构光电性质的理论研究  

Theoretical study of optical and electronic properties of silicether/graphether heterostructure

作　　者：张颖[1] 刘春生[1] Zhang Ying;Liu Chun-Sheng(College of Electronic and Optical Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学电子与光学工程学院,南京210023

出　　处：《物理学报》2021年第12期70-77,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61974068,11704198)资助的课题。

摘　　要：继石墨烯被发现合成之后,二维石墨醚及硅醚材料被预测为新型半导体.基于密度泛函理论的第一性原理计算,对硅醚/石墨醚异质结构的电子和光学性质进行了系统的研究.结果表明:当层间距为2.21?时,石墨醚的凹氧原子位于硅醚的凹氧原子之上的堆砌方式是最稳定的.此外,它的间接带隙为0.63 eV,小于石墨醚和硅醚的带隙.通过调节应变和电场强度,可以调整硅醚/石墨醚异质结构的带隙.特别是在压缩应变下,异质结构存在间接带隙向直接带隙的转变.硅醚/石墨醚异质结构的吸收系数在紫外光区出现强峰,与单层石墨醚和硅醚相比,异质结构的光吸收能力在80—170 nm范围内明显增强,结果表明硅醚/石墨醚异质结构具有突出的紫外吸收能力.本工作可为纳米器件提供一种具有潜在应用前景的新型材料.Since the discovery and synthesis of graphene,two-dimensional graphether and silicether materials have been predicted as novel semiconductors.A novel two-dimensional silicether/graphether heterostructure is designed by combining silicether and graphether,which has unique optical and electronic properties due to the properties of a single material synthesized by heterostructures.The electronic and optical properties of silicether/graphether heterostructure are studied by the first-principles calculations based on density functional theory.The binding energy and layer spacing for each of all considered 16 stacking patterns of the heterostructures are calculated.The results show that different stacking patterns have a small effect on the binding energy of the heterostructure.When the layer spacing is 2.21?,the stacking pattern in which the concave oxygen atoms of graphether are on the top of the concave oxygen atoms of silicether is the most stable.In addition,it has an indirect band gap of 0.63 eV,which is smaller than that of the silicether and graphether,respectively.By changing the external electric field and the biaxial strain strength,the band gap of the silicether/graphether heterostructure shows tunability.The compressive strain can increase the band gap of silicether/graphether heterostructure,while the band gap decreases with the tensile strain increasing.Especially,when the compressive strain is greater than–6%,the heterostructure undergoes an indirect-to-direct band gap transition,which is beneficial to its applications in optical devices.When the external electric field is applied,the band gap of the heterostructure changes linearly with the strength of the electric field,and the indirect band gap characteristic is maintained.The absorption coefficient of silicether/graphether heterostructure shows a strong peak in the ultraviolet light region.The maximum absorption coefficient can reach up to 1.7×105 cm–1 around 110 nm.Compared with that of monolayer graphether and silicether,the optical absorptio

关 键 词：第一性原理 硅醚/石墨醚异质结构 电子性质 光学性质 

分 类 号：TB34[一般工业技术—材料科学与工程]