径向压缩碳纳米管的电子输运性质  

Electron transport properties of carbon nanotubes with radial compression deformation

作　　者：林旖旎 马立[1] 杨权 耿松超 叶茂盛 陈涛[2] 孙立宁[2] Lin Yi-Ni;Ma Li;Yang Quan;Geng Song-Chao;Ye Mao-Sheng;Chen Tao;Sun Li-Ning(School of Mechatronic Engineering and Automation,Shanghai University,Shanghai 200072,China;Robotics and Microsystems Center,Soochow University,Suzhou 215021,China)

机构地区：[1]上海大学机电工程与自动化学院,上海200072 [2]苏州大学机器人与微系统研究中心,苏州215021

出　　处：《物理学报》2022年第2期260-270,共11页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2018YFB1309200);国家自然科学基金(批准号:61573238)资助的课题。

摘　　要：研究径向压缩形变对碳纳米管电子输运性质的影响对搭建微纳碳基电子器件具有重要意义.本文利用分子动力学模拟方法研究了碳纳米管与金属界面接触构型,得出碳纳米管径向压缩形变的规律.模拟结果表明:碳纳米管在水平接触金属表面后,其稳定状态下的径向压缩形变大小会受接触长度、管径大小、金属种类和片层数量的影响.基于紧束缚密度泛函理论和非平衡格林函数结合的第一性原理,系统地研究了不同直径、手性、片层、径向压缩形变碳纳米管的电子输运性质.研究表明:金属性单壁碳纳米管的电流呈线性增长趋势,且电流-电压的大小只与偏压有关,与直径大小无关;当其存在径向压缩形变时,电流在大偏压下增长趋势减缓,甚至会出现平台效应.半导体性单壁碳纳米管的导通电流随着径向压缩形变的增加而减小,电流-电压曲线逐渐从半导体特性向金属特性转变.随着径向压缩形变的增加,双壁碳纳米管的电流-电压曲线变化规律与金属性单壁碳纳米管的电流-电压曲线变化规律一致,但在相同偏压下,双壁碳纳米管的电流比单壁碳纳米管的电流高1倍;三壁碳纳米管的电流-电压曲线存在较大的振荡波动.In this paper,molecular dynamics simulation method is used to investigate the contacting configuration of carbon nanotubes with open ends and metal,thereby obtaining the law of radial compression deformation of carbon nanotubes.The obtained results show that after horizontally contacting the metal surface,the radial compression deformation is affected by the contact length,the diameter of the tube,the type of metal and the number of layers.Based on the first principles combining tight-binding density functional theory and non-equilibrium Green’s function,the electron transport properties of carbon nanotubes with different diameters,chiralities,lamellar deformations and radial deformations are systematically studied.The obtained results show that the current of metallic single-walled carbon nanotubes presents linear change in a bias voltage range between –2 V and 2 V,and the current-voltage curve is symmetrical about the origin.The magnitude of the current is only related to the bias voltage,but not to the diameter;when the carbon nanotubes are deformed by radial compression,the current growth trend is downward and even plateau effect may appear under a larger bias voltage.The current flowing in the semiconducting single-walled carbon nanotubes decreases with the increase of radial compression deformation,and the current-voltage curve gradually transforms from semiconductor characteristics into metallic characteristics.The trend of the current-voltage curve of double-walled carbon nanotubes is consistent with that of metallic single-walled carbon nanotubes.However,the non-linear variation amplitude of the current-voltage curve of double-walled carbon nanotubes is less affected by the radial compression deformation.Owing to the increase of walls of nanotubes,the current of double-walled carbon nanotubes is twice as high as that of single-walled carbon nanotubes under the same bias voltage.The electrons can produce transitions through rapid vibration between adjacent tubes,in view of the fact that interlayer cou

关 键 词：碳纳米管 电子输运性质 径向形变 第一性原理 

分 类 号：TQ127.11[化学工程—无机化工] TB383.1[一般工业技术—材料科学与工程]