In-situ formation of Are-MXY(M = Mo, W; (X ≠ Y) = S, Se, Te) van der Waals heterostructure

Abstract

Research domain of the photocatalytic water splitting and optoelectronics have received great attention in the current era of serious energy and environmental issues, because sunlight is needed only as energy input to produce oxygen and hydrogen. In present work, the hybrid first principle calculations are used to investigate the electronic structure, optical and photocatalytic response of strained Janus MXY and Arsenene (Are) monolayers, and their Are-MXY (M ​= ​Mo, W; (X ≠ Y) ​= ​S, Se, Te) van der Waals heterostructures (vdWHs). A direct to indirect bandgap transition is effectuated in induced strained MXY monolayers, while fabricating Are-MXY vdWHs. Stabilities(thermal/dynamic) of Are-MXY vdWHs are confirmed by calculating the binding energies and ab-initio molecular dynamics (AIMD) simulations. Electronic band structure calculations shows that Are-MXY vdWHs have semiconducting bandgap nature with type-I band alignment in case of the model-I of Are-MoSSe, Are-MoSTe, Are-MoSeTe, Are-WSTe and Are-WSeTe vdWH and model-II of Are-MoSeTe and Are-WSeTe vdWHs, while model-II of Are-MoSSe, Are-MoSTe, Are-WSSe and Are-WSTe vdWH show type-II band alignment. The calculations of Bader charges and electrostatic potential shows the transfer of charge from Are to MXY monolayer at the interface of Are-MXY vdWHs. Favorable positions of valence and conduction band edges of Are-MoSSe and Are-WSSe vdWH in model-II straddle redox potentials, hence, show suitability for the splitting of water at pH ​= ​0. Furthermore, absorption spectra are also investigated to understand the optical behaviour of the systems.