Regular Article

Electronic and optical properties of Janus monolayers MoXB₂ (X=S, Se): first-principles prediction

¹ School of Science, Wuhan University of Technology, Wuhan 430070, P.R. China
² Research Center of Materials Genome Engineering, Wuhan University of Technology, Wuhan 430070, P.R. China

^* e-mail: 16941612@qq.com

Received: 8 January 2021
Received in final form: 8 March 2021
Accepted: 18 March 2021
Published online: 15 April 2021

Abstract

By means of comprehensive first-principles calculations, we studied the geometric structure, the stability and electronic properties of the new two-dimensional (2D) Janus MoXB₂ (X=S, Se) monolayers. Our calculations demonstrated that the predicted Janus MoXB₂ monolayers are all stable semiconductors with direct band gap. In this paper, we focus on impacts upon the electronic and optical properties of the MoXB₂ monolayers under the different biaxial strains. With the compressive stress increases, the MoXB₂ monolayers would become indirect band gap semiconductors, and then behave as semimetal. While under tensile strain, MoXB₂ still maintain direct band gap. In addition, the optical calculation shows that biaxial strain leads to blue shifts in the optical absorption and reflectivity. The result indicates that MoXB₂ may be promised nano candidate materials in optoelectronic devices.