Tunable optoelectronic properties and high power conversion efficiency of AsP/MoSi2P4 van der Waals Heterostructure

Abstract

We present a systematic investigation of electronic and optical properties of the AsP/MoSi₂P₄ van der Waals heterostructure (vdWH) using first-principles calculations. Among the six possible stacking configurations considered, the AA and AB structures are predicted as most energetically favorable nanostructures via binding energy calculations. The ab initio molecular dynamics simulations further confirm the thermal stability of these heterostructures at room temperature. Both configurations exhibit semiconducting behavior, with band gaps of 0.712 eV and 0.710 eV, corresponding to type-I and type-II band alignments, respectively. Furthermore, strain engineering is applied to tune the electronic properties of the heterostructures. The band gaps of both stackings can be effectively modulated from 0 to 0.85 eV, accompanied by a transition in band alignment under vertical strain ranging from -0.2 Å to -0.8 Å. In addition, uniaxial strain induces an indirect-direct-indirect band gap transition around -1%. The calculated optical properties demonstrate that both stacking configurations of the AsP/MoSi₂P₄ vdWH possess significantly enhanced visible-light absorption compared with their constituent monolayers, with a notable power conversion efficiency (PCE) of 17.03% achieved in the -4% compressively strained AA stacking. Our study provides a comprehensive understanding of the electronic and optical behavior of the AsP/MoSi₂P₄ heterostructure, highlighting the effects of stacking order and mechanical strain, thereby offering valuable insights for the design of optoelectronic devices.