Light emission from ion beam induced silicon nanoclusters in silicon dioxide: role of cluster-cluster interactions via a thin oxide

Si nanoclusters are formed in a SiO2 matrix by ion implantation and anneali ng, and a possible mechanism for the light emission from Si implanted SiO2 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 an nealing 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 d ose of implanted Si ions especially in the high dose range. These results i ndicate that the emission of photon is not simply due to direct electron-ho le recombination inside Si nanoclusters, but is related to defects probably at the interface between Si nanoclusters and SiO2. for which the energy st ate is affected by Si cluster-cluster interaction. It seems that Si nanoclu sters react via a thin oxide interface and the local concentrations of Si n anoclusters plays an important role in the peak energy of the photoluminesc ence. (C) 1999 Published by Elsevier Science B.V. All rights reserved.