Crystalline anisotropy of β-Ga2O3 thin films on a c-plane GaN template and a sapphire substrate

In this work, crystalline anisotropy of heteroepitaxial ((2) over bar 01) beta-Ga2O3 films on a c-plane sapphire substrate and a GaN template was investigated using x-ray diffraction. The ((2) over bar 01) omega-scan broadening of beta-Ga2O3 on GaN exhibited six-fold rotational symmetric anisotropy along different azimuths, with maxima along the [010] direction and minima along the [102] direction, respectively. However, in beta-Ga2O3 on sapphire, it was nearly isotropic. Smaller lattice mismatch between beta-Ga2O3 and GaN were taken into account to explain the discrepancy, which also explained the better quality of beta-Ga2O3 deposited on GaN. Our results present a new viewpoint of the crystallographic anisotropy of ((2) over bar 01) beta-Ga2O3 thin films.