First-principles study of ZnO/MoSeTe van der Waals heterostructures for photovoltaic and hydrogen evolution applications

Abstract

2D heterostructures possess unique characteristics with potential applications in photocatalytic and photovoltaic devices. In this study, the electronic characteristics of ZnO, Janus MoSeTe monolayers, and heterostructures were investigated using density functional theory calculations. The 2D ZnO and Janus MoSeTe compounds were used to create the ABI-Se, ABI-Te, and ABII-Te stacking configurations. The evaluated 2D ZnO/MoSeTe heterostructures have an indirect band gap semiconductor with an electronic band gap of 1.355 eV, which is suitable for photovoltaic applications. The calculated lattice mismatch for the ZnO/MoSeTe heterostructure is 3.72%, which falls within the acceptable range for experimental realization of van der Waals (vdW) heterostructures. The evaluated power conversion efficiencies (PCE) of the three ZnO/MoSeTe heterostructures are 22.26%, 22.31%, and 22.17% for the ABI-Se, ABI-Te, and ABII-Te stacking configurations, respectively. These heterostructures meet some criteria for water splitting; however, they do not straddle both the conduction band minimum (CBM) and valence band maximum (VBM). The heterostructures satisfy the criteria as potential effective catalysts for the hydrogen evolution reaction (HER). Thus, the 2D ZnO/MoSeTe heterostructures with a high PCE of 22.31%, type-II band alignment, and HER potentials are viable candidate materials for photovoltaic and photocatalytic applications.