AgxO samples prepared in different O-2 gas ratio conditions and annealed at different temperatures have been studied by the spectroscopic ellipsometry, XRD and XPS methods. The optimal O-2/(O-2 + Ar) gas ratio for the sample preparation will be in the range 0.5-0.6, in which the optical constants become less changed. During annealing, the as-deposited amorphous structure of AgxO will be crystallized and the temperature-dependent decomposition will occur. The threshold of the decomposition temperature for AgO and Ag2O is approximately 200 degreesC and 300 degreesC, respectively. The results indicate that the samples annealed at the low and high O-2/(O-2+Ar) gas ratio will have different structures, and the structure of Ag2O is more stable with a lower oxygen diffusion rate in decomposition for the sample prepared in the higher O-2 gas ratio condition. (C) 2003 Elsevier B.V. All rights reserved.