The p-type modulation of by Ca and Cd doping

¹ College of Physics, Taiyuan University of Technology - Taiyuan, 030024, China
² College of Materials Science and Engineering, Taiyuan University of Technology - Taiyuan, 030024, China
³ Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering - Taiyuan, 030001, China
⁴ Hongzhiwei Technology (Shanghai) Co. Ltd. - 1599 Xinjinqiao Road, Pudong, Shanghai, China
⁵ College of Electronic Information and Optical Engineering, Taiyuan University of Technology Taiyuan, 030024, China
⁶ State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences Beijing, 100190, China

Received: 25 January 2024
Accepted: 22 May 2024

Abstract

Two-dimensional (2D) Bi₂O₂Se has been widely used as optoelectronic detector due to its excellent carrier mobility and environmental stability. However, the synthesis of the p-type Bi₂O₂Se remains challenging which hinders its further applications. In this paper, we have investigated the electronic properties of the native point defects and the Ca/Cd-doping effects on Bi₂O₂Se using first-principles calculations. The results indicate that Se vacancy (V_Se) and O vacancy (V_O) are shallow donors, which lead to the n-type Bi₂O₂Se semiconductor. Ca substituting Bi (Ca_Bi) and Cd substituting Bi (Cd_Bi) are acceptors and can compensate the n-type behavior of shallow donors. The compensation effect of Cd_Bi is weaker than that of Ca_Bi due to its higher formation energies. Additionally, the calculation results of the Fermi level, defect and carrier concentrations indicate that Ca_Bi shifts the Fermi level towards the valence band maximum (VBM), however, it is not sufficient to convert Bi₂O₂Se into the p-type.