Abstract
Indium nitride (InN) films were grown on the c-face of zinc oxide (ZnO) single crystals by molecular beam epitaxy, and their interfacial structure and crystalline polarity were examined. The c-parameter and the crystallinity of the films strongly depended on the substrate polarity and growth temperature. In particular, the low-temperature-grown films on the oxygen terminated c(−)-face of ZnO (c(−)-ZnO) were single crystalline films with a shorter c-axis than that of bulk InN, while the films grown on the zinc terminated c(+)-face of ZnO (c(+)-ZnO) and the high-temperature-grown films had low crystallinity. Coaxial impact-collision ion scattering spectroscopy (CAICISS) revealed that the low-temperature-grown films on c(−)-ZnO had (0001) In-faces, namely c(+)-polarity (c(+)-InN), and TEM observations suggested the existence of an interfacial layer a few atomic thick in the c(+)-InN/c(−)-ZnO heterostructure. These results on the lattice restriction and the polarity of InN films are discussed in terms of the interfacial structure at the InN/ZnO boundary.
