Au-Al2O3 nanocomposite films are prepared with different An contents on quartz substrates by radio frequency co-sputtering technique and annealed at different temperatures. The interactions between the Au nanoparticles and alumina matrix have been studied using X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR). XPS analysis reveals that both the Al and O atoms of the matrix are affected by the presence of Au nanoparticles and also by annealing the samples. For the as-grown example, the Al 2p peak shifts towards higher energy upon metal incorporation, whereas O 1s peak shifts towards lower binding energy. The shift of the binding energies could be due to the redistribution of electronic charge in Al2O3 caused by the incorporation of the Au nanoparticles. Due to the high electronegativity, the incorporated Au does not form any oxide in alumina. On the other hand, Au of the alumina matrix forms Al2Au alloy at the metal-oxide interface at room temperature. Annealing the composites at temperatures higher than 200degreesC breaks the Al2Au alloy leaving the Au in its elemental state. Infrared absorption measurements reveal the formation of Au-3 clusters in alumina due to Au incorporation. Evolutions of the metal-oxide interface state and IR absorption peak with the variation of annealing temperature of the films has been studied. (C) 2004 Elsevier B.V. All rights reserved.