Abstract
Epitaxial ZnO films were grown by a new technique, complex beam epitaxy. Highly oriented ZnO films grew at various substrate temperatures on (0001) Al2O3 substrates with and without the existence of surface lattice steps. The existence of the surface lattice steps had a strong effect on the enhancement of the orientation degree. The nonstepped substrate induced multinucleation growth of the crystals, although crystals grew epitaxially on the alumina substrate. In contrast, the stepped substrate promoted epitaxial lateral growth and coalescence of the crystallites at relatively high substrate temperatures ranging between 600 °C and 650 °C. These crystals generated free exciton luminescence in the UV region on 355 nm Nd:YAG laser irradiation.