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

Rapid design and development of the emergent ultrawide-bandgap semiconductors [Formula: see text] and [Formula: see text] require 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 [Formula: see text]- and [Formula: see text]-phases of [Formula: see text] and [Formula: see text] throughout their reciprocal spaces. Application of this model to [Formula: see text]-[Formula: see text]-[Formula: see text] superlattices reveals that intersubband transitions can be engineered to the [Formula: see text] telecommunications wavelength, opening new directions in oxide photonics. Furthermore, by accurately reproducing the bandgap, orbital character, 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.