First-Principles Investigation of Phase Stability, Electronic Structure and Optical Properties of MgZnO Monolayer

Changlong Tan; Dan Sun; Xiaohua Tian; Yuewu Huang

doi:10.3390/ma9110877

First-Principles Investigation of Phase Stability, Electronic Structure and Optical Properties of MgZnO Monolayer

Materials (Basel). 2016 Oct 27;9(11):877. doi: 10.3390/ma9110877.

Authors

Changlong Tan¹, Dan Sun², Xiaohua Tian³, Yuewu Huang⁴

Affiliations

¹ College of Applied Science, Harbin University of Science and Technology, Harbin 150080, China. changlongtan@hrbust.edu.cn.
² College of Applied Science, Harbin University of Science and Technology, Harbin 150080, China. wyysundan@163.com.
³ College of Applied Science, Harbin University of Science and Technology, Harbin 150080, China. xiaohuatian@hrbust.edu.cn.
⁴ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China. wuyuehuang@gmail.com.

Abstract

MgZnO bulk has attracted much attention as candidates for application in optoelectronic devices in the blue and ultraviolet region. However, there has been no reported study regarding two-dimensional MgZnO monolayer in spite of its unique properties due to quantum confinement effect. Here, using density functional theory calculations, we investigated the phase stability, electronic structure and optical properties of Mg_xZn_1-xO monolayer with Mg concentration x range from 0 to 1. Our calculations show that MgZnO monolayer remains the graphene-like structure with various Mg concentrations. The phase segregation occurring in bulk systems has not been observed in the monolayer due to size effect, which is advantageous for application. Moreover, MgZnO monolayer exhibits interesting tuning of electronic structure and optical properties with Mg concentration. The band gap increases with increasing Mg concentration. More interestingly, a direct to indirect band gap transition is observed for MgZnO monolayer when Mg concentration is higher than 75 at %. We also predict that Mg doping leads to a blue shift of the optical absorption peaks. Our results may provide guidance for designing the growth process and potential application of MgZnO monolayer.

Keywords: MgZnO monolayer; electronic structure; optical property; phase stability.