Strain-tunable III-nitride/ZnO heterostructures for photocatalytic water-splitting: A hybrid functional calculation

Zhaofu Zhang,Bingquan Huang,Xi Tang,Zhibin Gao,Baikui Li,Qingkai Qian

doi:10.1063/5.0005648

Abstract

Solar to fuel energy conversion is one of the momentous topics nowadays considering the urgent demand for clean energy supplies. In this work, the tunable electronic and optical properties of III-nitride/ZnO 2D/2D heterostructures (including GaN/ZnO, AlN/ZnO, and GaN/AlN) by strain engineering were investigated by first-principles calculations. The studied heterostructures feature a small interlayer distance, with the cation of one layer directly above the anion of the other layer, and vice versa. This leads to a strong binding energy and interlayer coupling across the heterostructure. The built-in field induced by the charge redistribution facilitates the photoexcited carrier migration, which is beneficial to the photocatalytic water splitting application. The stable III-nitride/ZnO heterostructures exhibit decent band edge positions with biaxial strain engineering and feature an enhancement of optical absorption under tensile strain. Our results indicate that the III-nitride/ZnO 2D/2D heterostructures are promising photocatalysts for solar to hydrogen generation by water splitting.

Highlights

With the rapid development of the contemporary industry, fossil fuel is being extensively consumed, which can lead to serious environmental issues
All the calculations in this work were conducted based on density functional theory (DFT) implemented in the VASP code
In contrast to the widely reported van der Waals heterostructures, these wide bandgap semiconductor 2D heterostructures show a much smaller layer distance as well as a stronger interlayer interaction and charge transfer

Summary

Introduction

With the rapid development of the contemporary industry, fossil fuel is being extensively consumed, which can lead to serious environmental issues. It is a mainstream issue to find sufficient renewable and clean energy supplies. Solar to fuel is a technologically feasible approach to effectively tackle the energy crisis.. Photocatalytic water splitting using semiconductors as catalysts to generate hydrogen stands out as a sustainable strategy for the generation of solar energy.. For high-efficiency photocatalyst in solar energy conversion applications, reasonable band edge positions with the respect to water redox potentials and suitable bandgap values are required.. Two-dimensional (2D) semiconductor materials with the high surface area–volume ratio, low defect concentration, and tunable bandgap value are promising candidates for high-efficiency photocatalytic water-splitting Solar to fuel is a technologically feasible approach to effectively tackle the energy crisis. Photocatalytic water splitting using semiconductors as catalysts to generate hydrogen stands out as a sustainable strategy for the generation of solar energy. For high-efficiency photocatalyst in solar energy conversion applications, reasonable band edge positions with the respect to water redox potentials and suitable bandgap values are required. In addition, the photo-excited electrons and holes should possess a long lifetime for effective separation to improve the water splitting efficiency. Two-dimensional (2D) semiconductor materials with the high surface area–volume ratio, low defect concentration, and tunable bandgap value are promising candidates for high-efficiency photocatalytic water-splitting

Methods

Results

Conclusion