Tunable optoelectronic properties and high power conversion efficiency of the AsP/MoSi2P4 van der Waals heterostructure.

We present a systematic investigation of electronic and optical properties of the AsP/MoSi2P4 van der Waals heterostructure (vdWH) using first-principles calculations. Among six possible stacking configurations, the AA and AB structures are predicted to be the most energetically favorable nanostructures based on binding energy calculations. The ab initio molecular dynamics simulations further confirm the thermal stability of these heterostructures at room temperature. Both AA and AB 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 0.75 eV under vertical strain ranging from -0.2 Å to -1.0 Å. In addition, the uniaxial strain induces transition between direct and indirect band gaps for both stackings. 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 under -4% compressive strain in the 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.