Formation of Au nanoparticles in silica by post-irradiation and thermal annealing

SiO2 + Au thin films were prepared on SiO2 substrates using ion beam assisted deposition (IBAD). The film was annealed at different temperatures. After each annealing, the optical absorption spectrum was taken to monitor the gold nanocluster formation in the thin film. By using Doyle’s formula, the size of the nanoclusters was determined and plotted as a function of the annealing temperature. Separately, other identical films were bombarded with ions of different energies and different fluence to monitor the nanoclusters forming during the bombardments. We have compared the effect of electronic energy deposition of the energetic ions with the effect of annealing at various temperatures.