Structural properties of InN films grown on O-face ZnO(0001) by plasma-assisted molecular beam epitaxy

We study the impact of substrate temperature and layer thickness on the morphological and structural properties of InN films directly grown on O-face ZnO(0001) substrates by plasma-assisted molecular beam epitaxy. With increasing substrate temperature, an interfacial reaction between InN and ZnO takes place that eventually results in the formation of cubic In₂O₃ and voids. The properties of the InN films, however, are found to be unaffected by this reaction for substrate temperatures less than 550 °C. In fact, both the morphological and the structural quality of InN improve with increasing substrate temperature in the range from 350 to 500 °C. High quality films with low threading dislocation densities are demonstrated.