Tight-binding band structure of β- and α-phase Ga2O3 and Al2O3

Rapid design and development of the emergent ultra-wide bandgap semiconductors Ga$_2$O$_3$ and Al$_2$O$_3$ requires a compact model of their electronic structures, accurate over the broad energy range accessed in future high-field, high-frequency, and high-temperature electronics and visible and ultraviolet photonics. A minimal tight-binding model is developed to reproduce the first-principles electronic structures of the $\beta-$ and $\alpha-$ phases of Ga$_2$O$_3$ and Al$_2$O$_3$ throughout their reciprocal spaces. Accurately reproducing the bandgap, orbital character, and effective mass and high-energy features of the conduction band, this compact model will assist in the investigation and design of the electrical and optical properties of bulk materials, devices, and quantum confined heterostructures.