Heteroepitaxial growth of ZnO thin films on spinel (111) substrates by using a low-temperature hydrothermal route

Epitaxial ZnO thin film was grown on spinel (111) substrates by using a hydrothermal technique. The phase and the surface morphology of the ZnO thin films were studied by using X-ray diffraction and field emission scanning electron microscopy. The as-grown film was c-axis oriented and had a rough pitted surface morphology. The thickness of the film was found to depend greatly on the initial precursor concentration. Room-temperature photoluminescence measurements were carried out to study the optical properties of the as-grown epitaxial ZnO thin films. Band edge luminescence due to excitonic recombination and deep-level emission peaks were observed.