Refractive index of β-Ga2O3; First-principles calculations

Abstract

β-phase gallium oxide (β-Ga₂O₃) is a semiconductor with a wide bandgap of approximately 4.8 to 5.04 eV, capable of transmitting light across a broad spectrum from infrared to ultraviolet. This property makes it a promising candidate for applications in wide-range devices such as power supplies, telecommunications, and high-voltage power switching. Recent measurements of the refractive index (n) in the terahertz (THz) region have revealed optical anisotropy between the b- and c-axis directions, with nc > nb. To determine whether this anisotropy persists across a wide wavelength range, we theoretically evaluate the contributions of phonons and electronic states to the refractive index.