Effective uniaxial dielectric function tensor and optical phonons in (2 ¯ 01)-oriented β - Ga2 O3 films with equally distributed sixfold-rotation domains
Monoclinic β-Ga2O3 films grown on c-plane sapphire have been shown to exhibit six (2¯01)-oriented domains, which are equally spaced by rotation around the surface normal and equally sized by volume that render the film optical response effectively uniaxial. We derive and discuss an optical model suitable for ellipsometry data analysis of such films. We model mid- and far-infrared ellipsometry data