  Silicon nanocrystals are produced using a two-stage gold ion implantation
technique. First stage implantation using low energy ions leads to the
formation of an amorphous Si (a-Si) layer. A subsequent high energy Au
irradiation in the second stage is found to produce strained Si NCs. An
annealing at a temperature as low as 500$^o$C is seen to result in strain free
NCs showing quantum confinement effects. Higher temperature annealing of the
samples is found to result in growth in size from recrystallization of the a-Si
matrix. Raman Scattering, X-ray diffraction (XRD) and Rutherford Backscattering
spectrometry (RBS) have been used to study the effect of annealing on the
samples and the size of Si NCs formed. The data could be well explained using a
phonon confinement model with an extremely narrow size distribution. XRD
results go in line with Raman analysis.
