Electronic structures and optical properties of Si- and Sn-doped β-Ga2O3: A GGA+U study**Project supported by the Science and Technology Program of Guangdong Province, China (Grant No. 2015B010112002) and the Science and Technology Project of Guangzhou City, China (Grant No. 201607010250).

Abstract

The electronic structures and optical properties of β-Ga2O3 and Si- and Sn-doped β-Ga2O3 are studied using the GGA + U method based on density functional theory. The calculated bandgap and Ga 3d-state peak of β-Ga2O3 are in good agreement with experimental results. Si- and Sn-doped β-Ga2O3 tend to form under O-poor conditions, and the formation energy of Si-doped β-Ga2O3 is larger than that of Sn-doped β-Ga2O3 because of the large bond length variation between Ga–O and Si–O. Si- and Sn-doped β-Ga2O3 have wider optical gaps than β-Ga2O3, due to the Burstein–Moss effect and the bandgap renormalization effect. Si-doped β-Ga2O3 shows better electron conductivity and a higher optical absorption edge than Sn-doped β-Ga2O3, so Si is more suitable as a dopant of n-type β-Ga2O3, which can be applied in deep-UV photoelectric devices.