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Si nanoclusters are formed in a SiO 2 matrix by ion implantation and annealing, and a possible mechanism for the light emission from Si implanted SiO 2 layers is reported. We have measured dose (concentration of excess Si atoms), annealing time and excitation energy dependence of the photoluminescence. After annealing, a photoluminescence band around 1.7 eV has been observed. The peak energy of the photoluminescence is found to be independent of annealing time and excitation energy, while the intensity of the luminescence increases as the annealing time and excitation energy increase. Moreover, we found that the peak energy of the luminescence is strongly affected by dose of implanted Si ions especially in the high dose range. These results indicate that the emission of photon is not simply due to direct electron–hole recombination inside Si nanoclusters, but is related to defects probably at the interface between Si nanoclusters and SiO 2 , for which the energy state is affected by Si cluster–cluster interaction. It seems that Si nanoclusters react via a thin oxide interface and the local concentrations of Si nanoclusters plays an important role in the peak energy of the photoluminescence. |
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