Enhanced ultraviolet emission due to surface plasmon resonance in ZnO/Ag
Li Xiu;Xu Yanfang;Xin Zhiqing;Li Yaling;Li Luhai;Beijing Institute of Graphic Communication, Beijing Engineering Research Center of Printed Electronics;
To improve the photoluminescence intensity of ZnO, the optical properties of ZnO/Ag structures were systematically investigated. The radio-frequency magnetron sputtering technique was adopted to deposit ZnO and Ag thin films on Si substrates. The optical properties of ZnO/Ag structures that significantly different from those of pure ZnO thin films at different sputtering time were demonstrated in detail. The photoluminescence intensity of ZnO/Ag films was carried out compared with that of the pure ZnO. The results reveal that, the photoluminescence spectra of bare ZnO film showed a weak bandgap emission at around 378 nm and a broad defect-related emission band centered at 470 nm.After adding Ag film, it resulted in an increase and decrease of the near band edge, meanwhile, the position of UV peak has as lightred-shift compared with that of pure ZnO thin film. The optical features can be influenced by the evolution of the Ag film varied with the deposition time. The reasons for the enhancement of the band edge emission which caused by the surface plasmon resonance coupling of the near band edge emission between Ag and ZnO was detailed discussed.