摘要
Small amount of (1013) ZnO domains were found in the m-plane ZnO films grown on m-sapphire by pulsed laser deposition, which provide strain relaxation of the m-ZnO matrix behaving as a low strain layer. Through carefully correlating low-temperature polarized photoluminescence spectra with the x-ray diffraction peak intensity ratio of (10 1 3) Z n O / (10 1 0) Z n O of the samples grown at different temperature and after thermal treatment, we found that the broad-band emission around 3.17 eV may result from the interface defects trapped excitons at the boundaries between the (10 1 3) Z n O domains and the m-ZnO matrix. The more (10 1 3) Z n O domains in the m-ZnO layer cause the more surface boundary that makes the stronger surface-bound-exciton emission. And the a-axes of both the (10 1 3) Z n O domains and the m-ZnO matrix are aligned with the c-axis of the sapphire (α-Al 2 O 3 ) substrate. The c-axis of the (10 1 3) Z n O domains rotates by about ±59° against the common a-axis of the m-ZnO. © 2012 American Institute of Physics.