A novel two-dimensional GaN/InGaN heterostructure for photocatalytic water splitting: A first-principles calculation

Abstract

The pursuit of optimal bandgap and band edge positions is crucial for effective photocatalytic catalysts, leading to significant attentions in both experimental and theoretical research on modulating the band structure of semiconductor photocatalysts. In this study, the electronic, optical and photocatalytic properties of 2D monolayer GaN and GaN/InGaN heterostructures are investigated using DFT calculations. It reveals that introducing strain is an effective approach to not only alter the band gap type from indirect to direct but also influence the magnitude of the band gap. At a 10% tensile strain, a Z-type heterostructure is formed for the 2D GaN/InGaN heterostructures, which proves favorable for enhancing the efficiency of photocatalytic water splitting. However, it is worth noting that the band gap type remains indirect, necessitating additional energy for electron transitions. On the other hand, when increasing the compressive strain from − 2.5% to − 5%, the 2D GaN/InGaN heterostructure transforms from type I to type II, exhibiting direct band gaps with an enhanced light absorption range. This results in a significant redshift and increased optical absorption intensity within the visible light range, leading to a substantial enhancement in photocatalytic efficiency. Consequently, our findings demonstrate that the 2D GaN/InGaN heterostructure holds promising potential as a candidate material for efficient photocatalytic water splitting applications.