Structural relation and epitaxial properties of hexagonal InN and oxidized cubic In2O3

The epitaxial properties and structural relation between hexagonal InN and cubic In2O3 phases were studied by synchrotron X-ray scattering and X-ray photoelectron spectroscopy. The cubic bixbyite In2O3 phase on the sapphire(0001) substrate was formed after an annealing time of 10 min at 10−5 Torr after the hexagonal InN film was grown at 550 °C, above the dissociation temperature of InN, by RF-magnetron sputtering. The crystal orientation was cubic In2O3(222), parallel to Al2O3(0001) and parallel to hexagonal InN(0002) before the oxidation process. The cubic In2O3 phase was believed to be formed layer by layer by the oxidation of the hexagonal InN phase.