华东师范大学学报（自然科学版） ›› 2022, Vol. 2022 ›› Issue (4): 114-119.doi: 10.3969/j.issn.1000-5641.2022.04.011

• 物理学与电子学 • 上一篇    下一篇

C3N带隙调控的第一性原理研究

赵威, 袁清红*()   

  1. 华东师范大学 精密光谱科学与技术国家重点实验室, 上海　200241
  • 收稿日期:2021-04-23 出版日期:2022-07-25 发布日期:2022-07-19
  • 通讯作者: 袁清红 E-mail:qhyuan@phy.ecnu.edu.cn
  • 基金资助:
    国家自然科学基金(21673075)

Bandgap tuning of C3N: A first-principles study

Wei ZHAO, Qinghong YUAN*()   

  1. State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai　200241, China
  • Received:2021-04-23 Online:2022-07-25 Published:2022-07-19
  • Contact: Qinghong YUAN E-mail:qhyuan@phy.ecnu.edu.cn

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摘要：

采用基于密度泛函理论 (Density Functional Theory, DFT) 的第一性原理计算, 研究了堆垛方式、层数及外加电场对C3N的带隙调控. 考察了AA-1型、 AA-2型、 AB-1型和AB-2型这4种堆垛结构, 计算表明, AB-2型堆垛结构能量最为有利. 通过HSE06杂化泛函对带隙进行了精确计算, 发现AA型堆垛与AB型堆垛的双层C3N存在较大的带隙差异, AA型堆垛结构的带隙要明显小于AB型堆垛结构. 此外, 还发现C3N的带隙可由单层的1.21 eV调控到体相的0.69 eV; 通过施加外加垂直电场, 可以将具有AB-2型堆垛结构的双层、三层和四层C3N半导体调控为趋于零带隙的金属.

关键词: 第一性原理计算, C3N, 堆垛, 带隙调控

Abstract:

In this paper, bandgap tuning of C3N through the stacking pattern, layer number, and external electric field were investigated by employing first-principles density functional theory (DFT) calculations. Four stacking structures—namely AA-1, AA-2, AB-1, and AB-2—were investigated in our study; the calculation results showed that the AB-2 structure was the most energetically favorable. Accurate calculations of the bandgap by the HSE06 hybrid functional revealed a large bandgap difference between the C3N bilayers with AA and AB stacking; specifically, structures with AA stacking had much smaller bandgap than those with AB stacking. Moreover, we found that the bandgap of C3N decreases from 1.21 eV for a single layer to 0.69 eV for the AB-2 bulk structure. By applying a vertical electric field, the bandgap of a C3N bilayer, tri-layer, and four-layer with AB-2 stacking can be tuned to a nearly metallic state.

Key words: first-principles calculations, C3N, stacking, bandgap tuning

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