Effect of Ag Thin Films on the Photoluminescence of ZnO Films

摘要

The Ag-coated ZnO films were deposited on glass substrates using magnetron sputtering technique. Atomic Force Microscopy was employed to characterize the surface and the profile roughness of Ag-coated ZnO films. X-ray diffraction and X-ray photoelectron were used respectively to analyze the crystalline and chemical state of survey samples. The influence of capping Ag on the photoluminescence intensities of ZnO films has been investigated. The photoluminescence spectra were found to change as the deposited Ag varied with different deposition times and annealing temperatures. Relationships between the fabrication, characterization and performance of Ag-coated ZnO films are established. The results indicate that the diffusion of Ag into ZnO films and the upward bending of the energy band near the interface of ZnO/Ag led to the decrease of ultraviolet intensities of Ag-coated ZnO films. Due to the density of surface states on the bending of energy band, it is crucial to control the surface morphology of metal/ZnO for the enhancement of light emission.