Synchrotron X-ray diffraction studies of heteroepitaxial ZnO films grown by pulsed laser deposition

Heteroepitaxial ZnO films were grown by pulsed laser deposition on various substrates such as GaN-buffered C-Al₂O₃, C-Al₂O₃, A-Al₂O₃, and R-Al₂O₃. The epitaxy nature of the films was investigated mainly by synchrotron X-ray diffraction. The results showed that the GaN interlayer plays a positive role in growing an unstrained, well-aligned epitaxial ZnO film on the basal plane of Al₂O₃. Importantly, the ZnO film grown on R-Al₂O₃ has two differently aligned domains. The dominant (1 1 0) oriented domain has much better alignment in the in-plane direction than the minor portion of (0 0 1) oriented domain, while in the out-of-plane direction the two domains have almost the same mosaic distribution.