In the present study, a facile method is developed for the synthesis of graphene oxide-Ag nanocomposite (GOAg). The method involves the application of in situ photochemical deposition and growth processes under certain alkaline environments in the absence of chemical reductants and surfactants. Silver nanoparticles with monodisperse size are well dispersed on the surface of graphene oxide (GO). The roles of GO and NaOH in the formation of GOAg are discussed. A corresponding formation mechanism of GOAg is proposed. Fluorescence quenching and Raman enhancement are examined as well. (C) 2011 Elsevier B.V. All rights reserved.