Effect of vacancy defects on the electronic and mechanical properties of two-dimensional MoSi2N4

Abstract

MoSi₂N₄ is a recently fabricated 2-dimensional indirect bandgap semiconductor material that has attracted interest in various fields due to its promising properties. A defect-based thorough and reliable investigation of its physical properties is indispensable in this regard to explore its industrial applications in the future. In this work, a comprehensive vacancy defect-based analysis of the electronic and mechanical characteristics of this material is conducted with varying defect percentages. We have analyzed the gradual change in electronic properties of MoSi₂N₄ by performing first-principles density functional theory-based investigation and presented a detailed analysis for point vacancies ranging from 0.297% to 14.29%, revealing the transition of this monolayer from the semiconductor to metal phase. The gradual change in mechanical properties due to the defect introduction has also been reported and analyzed, where the Young's modulus, Poisson ratio, elastic constant, etc. are calculated by the stress–strain method using Matrix Sets (OHESS). Further, we extend the investigation to the exploration of thermal and topological characteristics and report the triviality of the MoSi₂N₄ material as well as the effect on specific heat, entropy, and free energy with respect to temperature. We believe that the results presented in this study could assist the process of incorporating MoSi₂N₄ in future 2D electronics.