拉伸变形对硅纳米管电子结构和光学性能的影响  

Study on Electronic Structure and Optical Properties of Silicon Nanotube with Tensile Deformation

作　　者：杨忠华[1,2] 刘贵立[1] 曲迎东[2] 李荣德[2] 

机构地区：[1]沈阳工业大学建筑工程学院,沈阳110870 [2]沈阳工业大学材料工程学院,沈阳110870

出　　处：《人工晶体学报》2015年第9期2507-2512,共6页Journal of Synthetic Crystals

基　　金：国家自然科学基金(51274142;50671069)

摘　　要：采用基于密度泛函理论的CASTEP程序,对单壁手扶椅型(6,6)硅纳米管施加不同程度的拉伸变形,研究其电子结构和光学性质。研究发现,拉伸变形使得硅纳米管的Si-Si键长增加,布居数减小,稳定性降低。拉伸变形过程中,导带底的电子明显向低能区偏移,而价带顶的电子向高能区移动,从而能隙宽度减小。同时,由于共价键对价带电子的束缚度降低,价电子更容易受激发向导带跃迁。拉伸变形能够增大硅纳米管的静态介电常数和实数部的吸收宽度,并使介电函数虚数部在低能区发生红移,从而硅纳米管的能隙宽度减小。在近紫外光波段,红外和可见光波段硅纳米管的发光效率随拉伸变形量的增加而提高。研究结果为硅纳米管在光电器件的应用提供理论基础。Using CASTEP program based on density functional theory,the electronic structure and optical properties of the single-walled armchair type（ 6,6） silicon nanotubes with different conditions of tensile deformation were studied. Research shows the length of Si-Si bond is extended,and the population of SiSi bond in silicon nanotube is decreased by tensile deformation,which reduces its stability. During the tensile deformation,the electron of conduction band bottom moves to low energy zone obviously and the electron of valence band top shifts upward to high energy zone,which minimizes the width of the energy gap. At the same time,the active degree of valence electron is improved by the covalent bond＇s constrain weakened,minimum energy required for transition from the valence electron to the conduction band is reduced. The tensile deformation can make static dielectric constants and absorption range of dielectric real part of silicon nanotube increase,the imaginary part of dielectric function show red shift,the energy gap width of silicon nanotube decrease. Because of this deformation,the luminous efficiency is improved in near ultraviolet band,infrared and visible light band. The results provide a theoretical basis for the silicon nanotube in applications of optoelectronic devices.

关 键 词：第一性原理 硅纳米管 电子结构 光学性质 

分 类 号：O469[理学—凝聚态物理]