Raman and x-ray studies of InN films grown by metalorganic vapor phase epitaxy

Thin InN films were deposited on the (0001) sapphire substrate at various temperatures from 325 to 600°C by metalorganic vapor phase epitaxy. We used Raman scattering and x-ray diffraction to investigate the film properties and crystalline structures. Significant line broadening, softening and intensity evolution were observed at the growth temperatures between 375 and 450°C. This can be attributed to the formation of the mixed hexagonal and cubic structures and the related dislocation defects. As the growth temperature is further increased, the hexagonal phase is found to be dominant in the deposited InN film.