ИСТИНА

Recently much attention is paid to silicon nanocrystals (nc-Si) structures due to their high luminescence yield. One of the methods of nc-Si structures preparation is SiOx thin layers deposition and subsequent high temperature annealing. Nanocrystals formation occurs at the annealing temperatures higher than some critical point, while at lower temperatures presumably amorphous nanoclusters grow. Samples were prepared by rf-deposition of a 500 nm SiO layer on quartz substrate. After deposition structures were annealed at the temperatures in the range from 350 oC to 1200 oC in N2 atmosphere. Clusters structure type determination was made using Raman spectroscopy method: for the samples annealed at temperatures higher than 900 oC a peak at 520 cm-1 was detected which is typical for crystalline Si. While for the rest of the samples such Raman spectrum peak was not observed, which indicates the amorphous nature of the Si clusters. It was also obtained that 900 oC is critical for the optical parameters: for the samples annealed at higher temperatures PL spectrum width becomes 1.5 times lower and PL peak signal intensity becomes almost ten times higher. At the same time samples with amorphous Si nanoclusters are characterized by comparatively high PL yield: integrate PL signal is only 4 times lower than for nc-Si structures. This fact together with low annealing temperature gives promise for possible application of amorphous nanoclusters structures in optoelectronics. 1. G. Franzo, S. Boninelli, D. Pacifici, F. Priolo, F. Iacona and C. Bongiorno, Sensitizing properties of amorphous Si clusters on the 1.54-µm luminescence of Er in Si-rich SiO2 // Appl. Phys. Lett., 2003, v. 82, p. 3871.