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.

利用第一性原理计算研究了GaN纳米线表面，尤其是Pt修饰的表面的氢气传感机理。建立了有关GaN纳米线和Pt装饰表面上氧化还原工艺的各种模型。结果表明，Pt装饰可有效促进氧化还原过程。在Pt的催化下，更深原子层中的原子将参与表面电荷转移。铂装饰还将增强表面电子性能的鲁棒性，有助于更充分的氧化还原过程。气体传感过程会导致导带迁移，并导致从直接带隙到间接带隙的不可逆转变。