层状graphene/WSSe范德瓦耳斯异质结电子特性和界面接触的理论研究  

Theoretical Study on Electronic Properties and Interfacial Contact of Layered Graphene/WSSe Van der Waals Heterojunction

作　　者：赵婷婷 ZHAO Tingting(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;Key Laboratory of Solidification Control and Digital Preparation Technology,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学材料科学与工程学院,大连116024 [2]大连理工大学,凝固控制与数字化制备技术重点实验室,大连116024

出　　处：《人工晶体学报》2022年第12期2080-2089,2124,共11页Journal of Synthetic Crystals

基　　金：国家自然科学基金(21233010)。

摘　　要：利用第一性原理计算方法研究了层间距和外部电场对graphene/WSSe范德瓦耳斯异质结的电子特性和界面接触的影响规律。由于范德瓦耳斯力作用,graphene和WSSe单层的电子特性可以被保留在graphene/WSSe异质结中。当形成graphene/WSSe异质结时,在石墨烯的狄拉克锥中可以发现小的带隙值(7 meV)。电荷转移产生的内建电场在有效阻碍光激发载流子复合中起着关键作用。与两个独立单层相比,graphene/WSSe异质结在可见光区域具有增强的光吸收,在光电子器件中展现出了潜在应用价值。此外,graphene/WSSe异质结在平衡层间距处显示出n型肖特基接触特性。层间距和外部电场都可以用来改变graphene/WSSe异质结的肖特基势垒高度和接触类型,并有效调节graphene狄拉克锥的位置。本文研究内容为graphene/WSSe异质结在纳米电子和光电子器件领域的应用提供理论依据。The electronic properties and interface contact of graphene/WSSe van der Waals heterojunction by means of tuning the interlayer distance and external electric field were studied by the first-principles calculation method. The electronic properties of constituent monolayers can be retained in graphene/WSSe heterojunction because of the van der Waals force. A small band gap value(7 meV) can be found in the Dirac cone of graphene in graphene/WSSe heterojunction. The built-in electric field generated by the charge transfer plays a key role in the effective hindrance of photoexcited carrier recombination. The graphene/WSSe heterojunction possesses enhanced optical absorption in the visible light range compared with two freestanding monolayers, implying its potential application in optoelectronic device. Besides, the graphene/WSSe heterojunction displays the n-type Schottky contact characteristics at the equilibrium interlayer distance. Both the interlayer distance and external electric field can be used to modify the Schottky barrier height and contact types of graphene/WSSe heterojunction, and effectively adjust the Dirac cone position of graphene. The research in this paper provides a theoretical basis for the fascinating applications of graphene/WSSe heterojunction in the fields of nanoelectronic and optoelectronic devices.

关 键 词：二维材料 异质结 第一性原理计算 肖特基接触 欧姆接触 电子特性 外部电场 

分 类 号：TB34[一般工业技术—材料科学与工程] O469[理学—凝聚态物理]