Chemical vapor deposition of epitaxial zinc oxide thin films on gallium nitride/sapphire substrates

Abstract

High-quality ZnO thin films were formed on (0002) oriented GaN/sapphire substrates by chemical vapor deposition (CVD) of Zinc acetylacetonate (Zn(C5H7O2)(2)) and oxygen. The surface morphology and crystallinity of the deposited ZnO thin films have been investigated using atomic force microscopy and X-ray diffraction. Low temperature photoluminescence spectra show that there is a sharp band edge emission positioned at 3.37 eV and the deep level emission is hardly seen. High-resolution transmission electron microscopy in cross section shows that ZnO is directly grown on GaN in epitaxy without any interlayer, and the ZnO/GaN interface remains atomically flat. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim.