Spectroscopic ellipsometry studies on β-Ga2O3 films and single crystal

Abstract

Anisotropic optical properties are investigated on β-Ga2O3 films and a single crystal by spectroscopic ellipsometry measurements. The π201 films grown on (0001) a-Al2O3 contain threefold in-plane rotational domains, and the refractive index and absorption coefficient a obtained by assuming an isotropic material are found to be smaller than those in the single crystal. By measuring the off-normal transmission ellipsometry spectra of the (010) β-Ga2O3 substrate, the optical anisotropy in a biaxial crystal as well as the gradual increase in a are recognized as origins of the scattering in optically determined bandgap energies.