Effects of localized surface plasmons on the photoluminescence properties of Au-coated ZnO films.

The ultraviolet (UV) emission from the Au-coated ZnO films was greatly enhanced and the visible emission was significantly suppressed compared with the un-coated ZnO films. Great changes in photoluminescence of ZnO films are attributed to the electron transfer between conduction band and defect levels through the localized surface plasmons. The increase of electron density in conduction band causes enhanced UV emission, while the decrease in electron density in defect level leads to the suppression of the visible emission. Such ZnO films with enhanced UV emission have potential applications in the highly efficient solid state emitters.