Hydrogen gas sensing mechanism of Pt-decorated GaN nanowire surface: A perspective from first principle study

The hydrogen gas sensing mechanism of GaN nanowire surface, especially Pt-decorated surface are investigated utilizing first principle calculations. Various models with respect to the redox process on GaN nanowire and Pt-decorated surfaces are built. The results indicate that Pt decoration can effectively promote the oxidation and reduction process. Atoms in deeper atomic layer will participate in surface charge transfer under the catalysis of Pt. Pt decoration will also enhance the robustness of surface electronic properties, contributing to a more sufficient redox process. The gas sensing process causes a migration of conduction band and an irreversible transition from direct to indirect band gap. This study is expected to give more evidences for the gas sensing mechanism on GaN nanowire surface and provide theoretical guidance for future experiments.