Photoluminescence of ZnO thin films grown on GaN templates by atmospheric pressure MOCVD

In this paper, we report the photoluminescence properties of ZnO thin films on (0 0 0 1) sapphire and GaN/c–Al2O3 template grown by atmospheric pressure metal–organic chemical vapor deposition (AP-MOCVD) using deionized water and diethylZinc as the O and Zn precursors, respectively. The two kinds of samples have very sharp band-edge PL emission at room temperature. The A and B exitons were clearly observed at 10 K in both samples, and the four phonon replicas and the C exciton or the first excited state of A exciton could be clearly observed in ZnO/GaN/Al2O3 film. The Huang–Rhys factor S of the ZnO/Al2O3 sample is two times larger than that of the ZnO/GaN/Al2O3 sample, which shows that the stronger exciton–phonon interaction in the ZnO/Al2O3 sample is stronger. The PL performance strongly suggests that high-quality ZnO films can be grown on the template of GaN/Al2O3 by AP-MOCVD.