Tuning the electronic, optical and structural properties of GaS/C2N van der Waals heterostructure for photovoltaic application: first-principle calculations

Abstract

Due to the increased energy demand, a large amount of renewable energy is required to sustain the lives of people. The visible light semiconductors for photovoltaic cells with optical properties and a tunable bandgap have been studied to bring the solution to energy crises. Two-dimensional (2D) semiconductors including gallium sulphide (GaS) and carbon nitride (C2N) monolayers as a photovoltaic material were investigated by designing GaS/C2N van der Waals (vdWs) heterostructure. In this study, density functional theory (DFT) was employed to study the structural, photovoltaic applications, electronic and optical properties of GaS/C2N vdWs heterostructure. In comparison with the counterparts of GaS and C2N monolayers, the GaS/C2N vdWs heterostructure showed a lower desirable direct bandgap of 1.251 eV and the projected density of states shows a type-I band alignment. The work function of the heterostructure is much lesser than the GaS monolayer and C2N layer, which signifies that less energy will be needed for electrons to transfer from the ground state. The charge density transfer shows charge redistribution from GaS to C2N. The power conversion efficiency (η) of GaS/C2N heterostructure is calculated to be 17.8%. Based on the results, the 2D GaS/C2N heterostructure is predicted to be effective material in developing a high-performance photovoltaic device for future use.