摘要： β-Ga2O3 has recently gained a lot of interest for applications in solar-blind deep ultraviolet (UV) detectors and high-power electronics at elevated temperatures. The interest stems from its intrinsic material properties, such as wide-bandgap nature (4.9 eV) and high breakdown electric field. β-Ga2O3 can also serve as a reactive oxide layer, sensitive to a wide variety of gases, especially at high temperatures in harsh environments. Many β-Ga2O3-based gas sensors have been reported recently [1–20]. In this chapter, the gas sensing mechanism and the sensing characteristics of β-Ga2O3 are reviewed. First, the material properties of β-Ga2O3 are reviewed for a clear understanding of surface reactions at oxide surfaces with various gas molecules. The crystal structure of β-Ga2O3 and the surface atomic configurations of 201 and (010)-oriented β-Ga2O3 are investigated. The wet and dry etching characteristics and the metal contact properties of 201 and (010) β-Ga2O3 single crystals are discussed for a broad range of device applications. Recent reports of β-Ga2O3-based hydrogen sensors are discussed, and the hydrogen sensing properties of 201 and (010) β-Ga2O3 single crystals are compared for enhanced hydrogen detection.