Enhancement of ultraviolet emissions from ZnO films by Ag doping

The Ag-doped ZnO films were deposited on Si substrates by dc reactive sputtering. Obvious enhancement of ultraviolet (UV) emission of the samples was observed due to Ag2O nanoclusters formatted during Ag doping. The UV emission consisted of two peaks. The 348 nm peak was attributed to Ag2O nanoclusters, and the 382 nm one was attributed to ZnO. The strongest UV emission of a certain ZnO-Ag2O film was over ten times stronger than that of a pure ZnO film, which was an exciting result. The enhancement of UV emission was caused by excitons formed at the interface between Ag2O nanoclusters and ZnO grains. (c) 2006 American Institute of Physics.