Preparation and characterization of silicon nanostructures obtained by ion implantation

Photoluminescence (PL) was used to investigate the luminescence mechanism in Si nanostructures. Si ions were implanted into SiO₂ films at 100keV with a dose of 5×10¹⁶cm^-2. Photoluminescence band in (1.1-1.9)eV was observed after implanted films have been annealed at 1000°C in nitrogen. Deconvolution of photoluminescence spectra suggests that different recombination centers possibly are present into the samples. Red PL band (1.5eV) was attributed to emission from Si nanostructures, because gaussian peak in the 1.5eV increases continuously with annealing temperature and becomes narrower. Raman spectra for all samples show a peak approximately at 521cm ^-1, related to typical crystalline silicon. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images were used to show the presence of Si nanostructures, which appears within a broad size distribution on etched annealed samples.