Optical properties in the Cu-fused silica system irradiated with swift heavy ions

Swift heavy ions are used to study the effects of electronic energy loss on Cu cluster formation in fused silica after post-irradiation annealing. Fused silica substrates covered with 10 nm thin Cu-films were irradiated using beams of either 120 MeV Ag9+ ions or 350 MeV Au26+ ions at fluences ranging from 2 x 1013 to 1 x 1014 cm-2. After irradiation, the samples were annealed for 30 min in argon, at temperatures of 773-1200 K and characterized by UV-VIS absorption spectroscopy. The swift ion irradiations created E' and B2 defects in silica, which were partially eliminated during annealing. In addition, Cu cluster formation in silica was observed after annealing. Irradiation fluences exceeding 4 x 1013 cm-2 and annealing temperatures above 1100 K are more effective in forming larger nanoclusters