ZnSe nanocrystals have been formed in the silicon dioxide matrix by the sequential high-fluence implantation of Zn + and Se + ions at 500°C. After implantation a part of samples was annealed at 1000°C for 3 min using rapid thermal annealing. Structural and optical properties of ZnSe/SiO 2 nano-composite films were analyzed by means of Rutherford Backscattering Spectrometry, cross-sectional Transmission Electron Microscopy, Raman scattering and photoluminescence techniques. It was shown that a sequence of implantation affects structural and optical properties of synthesized ZnSe clusters. Based on the Raman scattering and photoluminescence data the samples for which Zn ions were implanted first exhibited a better ZnSe crystalline quality than those of reverse sequence of implantation, i.e. with Se ions implanted at the beginning. The bands of blue ZnSe band edge emission and green-red ZnSe deep defect level emission were revealed in the PL spectra of the as-implanted and annealed nano-composites. The PL spectral features observed in the blue region are due to the quantum-size effects in the ZnSe nanocrystals embedded into the silicon dioxide matrix. The PL intensity ratio of the deep defect band to the near edge emission is higher in the samples first implanted with Se ions, and Zn ions implanted next. The effect of rapid thermal annealing on structural and light-emitting properties was discussed.
Selenium supersaturated silicon is a promising material for intermediate-band solar cells and extended infrared photodiodes. Selenium-rich Si layers were fabricated by Se ion implantation followed by pulsed laser melting using one or three pulses. The Rutherford backscattering spectrometry in random and channeling directions, the Raman spectroscopy, and photoluminescence techniques were used to study structural and optical properties of the Se-rich silicon layers. It is shown that laser irradiation leads to silicon recrystallization and significant impurity redistribution in the implanted layer. According to the Rutherford backscattering data, the substitutional fraction of Se atoms after laser treatment is 60-80%. The analysis of photoluminescence spectra revealed that pulsed laser irradiation of the implanted layer with the power density of 1.5 J/cm 2 leads to the formation of vacancy and interstitial Si clusters. After annealing at the power density higher than 1.5 J/cm 2 , the photoluminescence originating from vacancies and interstitials disappears. To explain the evolution of the Se distribution within the implanted layer after laser melting, numerical solution of the 1D diffusion equations was used.
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