Growth of \beta-Ga_2O_3 Films on Sapphire by Hydride Vapor Phase Epitaxy

Two-inch Ga_2O_3 films with (\bar201)-orientation are grown on c-sapphire at 850–1050^\circ\!C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure \beta-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in \beta-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 eV.