非对称氧掺杂对石墨烯/二硒化钼异质结肖特基势垒的调控  

Regulation and control of Schottky barrier in graphene/MoSe;heteojuinction by asymmetric oxygen doping

作　　者：郝国强[1] 张瑞[1] 张文静 陈娜 叶晓军[1] 李红波[1] Hao Guo-Qiang;Zhang Rui;Zhang Wen-Jing;Chen Na;Ye Xiao-Jun;Li Hong-Bo(School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China;School of Chemistry and Materials Science,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]华东理工大学材料科学与工程学院,上海200237 [2]中国科学技术大学化学与材料科学学院,合肥230026

出　　处：《物理学报》2022年第1期234-242,共9页Acta Physica Sinica

基　　金：上海市科委科技基金(批准号:17DZ1201405)。

摘　　要：在纳米逻辑器件中,制造低的肖特基势垒仍然是一个巨大的挑战.本文采用密度泛函理论研究了非对称氧掺杂对石墨烯/二硒化钼异质结的结构稳定性和电学性质的影响.结果表明石墨烯与二硒化钼形成了稳定的范德瓦耳斯异质结,同时保留了各自的电学特性,并且形成了0.558 eV的n型肖特基势垒.此外,能带和态密度数据表明非对称氧掺杂可以调控石墨烯/二硒化钼异质结的肖特基接触类型和势垒高度.当氧掺杂在界面内和界面外时,随着掺杂浓度的增大,肖特基势垒高度都逐渐降低.特别地,当氧掺杂在界面外时, n型肖特基势垒高度可以降低到0.112 eV,提高了电子的注入效率.当氧掺杂在界面内时, n型肖特基接触转变为欧姆接触.平面平均电荷密度差分显示随着掺杂浓度的增大,界面电荷转移数量逐渐增多,导致费米能级向二硒化钼导带底移动,证实了随着氧掺杂浓度增大肖特基势垒逐渐降低,并由n型肖特基向欧姆接触的转变.研究结果将对基于石墨烯的范德瓦耳斯异质结肖特基势垒调控提供理论指导.Although graphene-based heterostructures exhibit excellent intrinsic properties for device scaling,fabricating low Schottky barrier is still a great challenge to the electrical transport behaviors of nanoelectronic devices. Exploring excellent materials for electronic devices are a research hotspot at present. Graphene not only exhibits excellent physical strength and specific surface area, but also presents high carrier mobility and thermal conductivity. Therefore, graphene has been developed in many fields such as energy, catalysis, etc. However,graphene is a special material with zero band gap, and its electrons and holes are easy to compound, which seriously hinders its development in the applications of electronic and optoelectronic devices. Two-dimensional transition metal dichalcogenides(TMDs) have the advantages of controllable band gap properties, which makes them have a good development in logic circuits and photodetectors. As one of TMDS, MoSe;possesses the advantages of narrower band gap, better electron hole separation and stronger oxidation resistance in the environment. Therefore, the design of graphene and MoSe;heterostructures is an ideal choice for a new generation of nanoelectronic devices. Here, we investigate systematically the effects of asymmetric O doping on the electronic properties and Schottky barrier of graphene/MoSe;O;heterostructure for the first time by first-principles calculations incorporating semiempirical dispersion-correction scheme. The results indicate that graphene and MoSe;monolayer can form a stable van der Waals heterostructure with preserving their own intrinsic properties. In addition, an n-type schottky contact with a barrier height of 0.558 eV is obtained.Further, it is found that the type and the height of the Schottky barrier can be controlled by changing the concentration and sites of the O dopant at interface. By increasing the concentration of the O dopant inside the interface, the transition from an n-type Schottky contact to an Ohmic contact can be realized, a

关 键 词：异质结 密度泛函理论 非对称掺杂 肖特基势垒 

分 类 号：TB34[一般工业技术—材料科学与工程]