Effect of growth temperature on a-plane ZnO formation on r-plane sapphire

Abstract

The effect of growth temperature on a-plane ZnO formation on r-plane sapphire has been systematically investigated by employing in situ high pressure reflection high-energy electron diffraction, atomic force microscopy, and high-resolution x-ray diffraction. For film growth above and below 600 degrees C, it is shown that there is a significant difference in growth rate and surface morphology due to the differences in the growth mode. Stripelike morphologies were observed on the surface of a-plane ZnO grown at low temperature (LT) because of differences in the growth rate along the c-axis and the growth rate normal to the c-axis. Furthermore, annealing of films grown at low temperature results in more pronounced stripe morphology and in improvement of crystallinity. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3549141]