Effect of insitu annealing on physical properties of Si nanoparticles synthesized by pulsed laser ablation

Silicon nanocrystalline particles with a uniform size were successfully synthesized by a sequential system of pulsed-laser ablation, insitu annealing and a size classification using a differential mobility analyzer (DMA). Transmission electron microscopy (TEM) observations revealed that the insitu annealing was quite effective in improving morphological uniformity of the particles; most of the nanoparticles annealed above a temperature of 900 °C showed a spherical shape. The silicon nanoparticles classified after the annealing showed a very narrow size-distribution with a geometrical standard deviation of approximately 1.1. Raman scattering measurement and high-resolution TEM observation showed that the annealing was also effective in improving a crystallinity of the particles. The silicon nanoparticles showed photoluminescence (PL) in near-IR and visible region at room temperature, which depended on the insitu annealing condition; the full-width at half-maximum (FWHM) of the PL spectrum decreased with the increase in annealing temperature and reached as narrow as 190 meV corresponding to the sharp size distribution of the emitting particles. PACS 81.40.Pq; 81.07.Bc