High-quality ZnO films grown by atmospheric pressure metal- organic chemical vapor deposition

 High-quality ZnO films grown by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) are demonstrated in this paper. Surface morphology, structural quality and optical properties of the As-grown films were investigated by AFM, double-crystal XRD and photoluminescence (PL) measurements. The effect of buffer layers grown at different temperature on the film quality was studied. It was found that the low-temperature buffer layer was effective to improve the surface morphology, but was not effective to improve the structural quality. On the other hand, the high-temperature buffer layer can greatly improve the structural quality, but yields a relatively rougher surface. Both the samples deposited using either a low-temperature or high-temperature buffer layer showed strong UV luminescence at room-temperature. A fine structure of free excitons was observed at 11 K in the sample with a high-temperature buffer layer.