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

摘要

In this paper, we report the photoluminescence properties of ZnO thin films on (0001) sapphire and GaN/c-Al_2O_3 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/Al_2O_3 film. The Huang-Rhys factor S of the ZnO/Al_2O_3 sample is two times larger than that of the ZnO/GaN/Al_2O_3 sample, which shows that the stronger exciton-phonon interaction in the ZnO/Al_2O_3 sample is stronger. The PL performance strongly suggests that high-quality ZnO films can be grown on the template of GaN/Al_2O_3 by AP-MOCVD.