First principles investigation of electron mobility enhancement of β-GaO doped with indium.

β-GaO is one of the new-generation wide-bandgap semiconductor materials that has attracted much attention in recent years. However, the reported room-temperature electron mobility of β-GaO is much lower than GaN and SiC. Alloying GaO is expected to endow the material with superior carrier transport properties. Herein, we mainly investigate the electron mobility of pure GaO, In-doped GaO, and Al-doped GaO from first-principles considering acoustic deformation potential (ADP) scattering, polar optical phonon (POP) scattering and ionized impurity (IMP) scattering. The structure optimization, electronic band structure, and temperature-dependent and concentration-dependent electron mobility are investigated. The results show that the mobility of In-GaO is always the highest at 105-650 K, and POP scattering is the dominant factor limiting the electron mobility from 150-650 K. The mobility enhancement by In-doping is attributed to the smaller effective mass caused by the In 5s state despite its slightly increased electron-phonon coupling strength. The predicted electron mobilities for GaO, Al-GaO and In-GaO at an electron concentration of 1.0 × 10 cm are 151.5 cm V s, 137.8 cm V s and 184.9 cm V s at room temperature, respectively. This work provides an alternative route to enhance the electron mobility of GaO and guides in engineering their electronic transport properties for high-power electronics.