This work experimentally verifies that surface plasmon (SP) coupling can enhance the yellow emission of Ce-doped Y3Al5O12 (YAG:Ce) thin-film phosphors. The effect of SP on yellow emission from YAG: Ce thin-film phosphor coated with a metal layer is examined. Among Ag, Al, and Au materials, the emission intensity of YAG: Ce thin-film phosphor by coating a silver layer with a thickness of nanometers was significantly enhanced by 10-fold. The enormous enhancement on photoluminescence (PL) is attributable to the resonant coupling of emission in YAG: Ce with an SP and the electric field of incident light at the metal interfaces. The mass thickness and annealing conditions of the deposited layer can be varied to transform the Ag layer into an islandlike structure; the PL intensity is highest at a Ag thickness of 20 nm. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3240324] All rights reserved.