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.