无机材料学报 ›› 2020, Vol. 35 ›› Issue (1): 73-78.DOI: 10.15541/jim20190278

所属专题: MAX相和MXene材料 MXene材料专辑(2020~2021)

• 研究论文 • 上一篇    下一篇

电场、应力和电荷态对Ti2CO2电子性质调控的理论研究

王昌英1,路宇畅2,任翠兰2(),王刚1,怀平2,3()   

  1. 1. 常州工学院 理学院, 常州 213032
    2. 中国科学院 上海应用物理研究所, 上海201800
    3. 上海科技大学 物质科学与技术学院, 上海 201210
  • 收稿日期:2019-06-06 修回日期:2019-09-03 出版日期:2020-01-20 网络出版日期:2019-10-25
  • 作者简介:王昌英(1988-), 女, 讲师. E-mail:wcy58462006@126.com
  • 基金资助:
    国家自然科学基金(11847064);国家自然科学基金(11605273);上海市自然科学基金(16ZR1443100)

Theoretical Studies on the Modulation of the Electronic Property of Ti2CO2 by Electric Field, Strain and Charge States

WANG Chang-Ying1,LU Yu-Chang2,REN Cui-Lan2(),WANG Gang1,HUAI Ping2,3()   

  1. 1. School of Sciences, Changzhou Institute of Technology, Changzhou 213032, China
    2. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, 3. School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
    3. School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
  • Received:2019-06-06 Revised:2019-09-03 Published:2020-01-20 Online:2019-10-25
  • About author:WANG Chang-Ying (1988-), female, lecturer. E-mail:wcy58462006@126.com
  • Supported by:
    National Natural Science Foundation of China(11847064);National Natural Science Foundation of China(11605273);Science and Technology Commission of Shanghai Municipality(16ZR1443100)

摘要:

MXene是一类具备丰富物理化学性质的新型二维过渡金属碳化物, 在储能、催化、复合材料、发光材料等领域都表现出潜在的应用前景。元素掺杂、结构缺陷、表面功能化、外加电场、外加应力等方法是调节二维材料性能的有效手段。作为厚度最小和最轻的含钛MXene材料, Ti2CO2具有间接半导体特性, 本工作研究外加电场、外加应力和电荷态等条件对Ti2CO2电学性能的调控。结果表明:无缺陷Ti2CO2原胞的带隙随着外加电场的增强而变小。在Ti2CO2体系中, 碳空位较易形成。研究发现拉伸应力可以改变含碳空位体系的导电能力, 费米能级附近的能带随着拉伸应力的增大而逐渐平滑。研究还发现电荷态会改变含碳空位2×2×1 Ti2CO2超胞的能带结构, 随着电荷态的增加, 体系费米能级的位置逐渐降低, 且电荷态为+2时, 含碳空位2×2×1 Ti2CO2超胞表现出半导体特性, 带隙类型转变为直接带隙, 带隙值为0.489 eV。

关键词: 第一性原理, Ti2CO2, 电场, 应力, 电荷态, 电子性质

Abstract:

As a new two-dimensional transition metal carbides, MXene has various potential applications, such as energy storage, catalyst, composite material, and luminescent materials for their excellent physical and chemical properties. The element doping, geometrical defect, surficial functionalization, external electric field, and external strain can be used as effective methods for modulation of their properties. Ti2CO2, the thinnest Ti-based MXene, exhibits semiconducting character. The effects of electric field on the band structure of perfect primitive Ti2CO2 were explored in this work. The results revealed that the band gap of perfect primitive Ti2CO2 decreased with the increasing electric field. Carbon (C) vacancy in Ti2CO2 MXene was easily produced during the preparation process. Further investigation showed that the tensile strain could be used to regulate the conductivity of this system as the bands around the Fermi energy become smoother with increasing tensile strain. The investigation of charged C vacancy doped 2×2×1 Ti2CO2 indicated that its Fermi energy decreased with the increase of charge state. When it was +2 charged, the C vacancy doped 2×2×1 Ti2CO2 exhibited semiconducting character and owned a direct band gap of 0.489 eV.

Key words: first-principles, Ti2CO2, electric field, strain, charge state, electronic property

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