Modulation of electronic structures and transport properties in 2D TM0.5Ga1.5O3 (TM = Al, Ga, In)

•Both 2D Al0.5Ga1.5O3 and 2D In0.5Ga1.5O3 are more readily formed under oxygen-poor conditions.•2D Al0.5Ga1.5O3 has a larger bandgap than 2D Ga2O3 and a lower electron mobility of 953.953 cm2·V−1·s−1.•The bandgap of 2D In0.5Ga1.5O3 is smaller than that of 2D Ga2O3 while its electron mobility is increased to 2262.901cm2·V−1·s−1.•2D Ga2O3, 2D Al0.5Ga1.5O3 and 2D In0.5Ga1.5O3 have anisotropic transport properties. In this study, the band structures, density of states and transport properties of two-dimensional (2D) TM0.5Ga1.5O3 (TM=Al, Ga, In) are investigated by the first principle and the deformation potential theory. Both 2D Al0.5Ga1.5O3 and 2D In0.5Ga1.5O3 alloys tend to form under poor-oxygen conditions. Compared to bulk Ga2O3, the bandgap of 2D Ga2O3 is increased by 0.382 eV and its electron mobility is significantly increased from 143.352cm2·V−1·s−1 to 1486.638cm2·V−1·s−1. For 2D Al0.5Ga1.5O3, the bandgap and the electron effective mass are larger than those of 2D Ga2O3, but its electron mobility is reduced by >25%. In contrast, the bandgap of 2D In0.5Ga1.5O3 is narrower than that of 2D Ga2O3 while its electron mobility is increased by >52%, reaching 2262.901cm2·V−1·s−1. Therefore, 2D In0.5Ga1.5O3 has great potential to be used as a transport material for high-speed Ga2O3 electronic devices.