Growth and characterization of silicon nanocrystals obtained by ion implantation

Experimental results on visible and near infrared photoluminescence (PL) at room temperature, Fourier transform infrared (FTIR) and high-resolution transmission electron microscopy (HRTEM), from Si nanocrystals (nc-Si) embedded in a SiO₂ matrix, are reported herein. The samples containing nc-Si was obtained by ion implantation and annealing of thermally grown SiO ₂, on a (100) silicon wafer. PL was measured for two groups of samples. One group consists of samples obtained by different implantation doses and annealing times. Another group consists of samples obtained by an unique dose and annealing time, subsequently treated with post-annealing gas treatments. For the first group, a peak at 663nm (1.87eV) was observed for all implantation doses and annealing times. Samples of the second group, treated with post-annealing at 450°C in environments of N₂, H₂ and forming gas (FG) showed an increasing of luminescence peak centered at 790nm (1.57eV). The post-annealing treatments showed that H₂ gas has a better performance for enhancing the PL intensity.