Using chemical solution process to fabricate zinc oxide micro/nano-structure on GaN with different growth time

High-quality single crystal ZnO thin film was grown on an GaN epitaxial layer through a simple low-temperature solution process. X-ray diffraction and field emission scanning electron microscopy shows that ZnO thin film is well oriented along the (0001) plane of GaN. Atomic force microscopy also reveals the ZnO thin film is extremely smooth on GaN. The photoluminescence spectrum for the ZnO-GaN hetero-structure showed a peak in the ultra-violet region and a broad band transition in the yellow emission range. Furthermore, this high-quality single crystal ZnO thin film has the potential to recycle the substrates to reduce the cost via chemical etching.