Influence of annealing and supersonic treatments on structure and photoluminescence of ZnO films

A series of ZnO thin films were deposited on silicon (100) substrate by facing target radio frequency magnetron sputtering system, and were annealed and supersonically treated. The samples were characterized by X-ray diffraction(XRD), atomic force microscopy(AFM), and photoluminescence(PL) spectrum. XRD results show that the as-deposited film has less preferential C-axis orientation, while increasing the annealing temperature gets preferential C-axis orientation better. The grain size of the sample becomes larger and the residual stress changes from compress stress to tensile stress with the increase of the annealing temperature. The PL spectrums indicate that there is no emission for the as-deposited film at room temperature. As the annealing temperature increases, both a 378 nm ultraviol