ANNEALING BEHAVIOR OF SILVER, COPPER, AND SILVER-COPPER NANOCLUSTERS IN A SILICA MATRIX SYNTHESIZED BY THE SOL-GEL TECHNIQUE

Silver, copper, and mixed silver-copper nanocluster-doped silica thin layers were prepared by the sol-gel process. Samples were heat treated in different annealing atmospheres (air, argon, or 5%c H-2-95%N-2) in the temperature range 500-1100 degrees C. Specimens were characterize d by optical absorption spectroscopy, Rutherford backscattering spectr ometry, x-ray diffraction, and transmission electron microscopy. Clust er growth and dissolution, as well as migration of metal atoms towards the sample surface, with a subsequent evaporation, were observed to o ccur at temperatures that depend on the annealing atmosphere. In the m ixed silver-copper system, the formation of Ag-Cu phase-separated clus ters was observed. (C) 1996 American Institute of Physics.