PHOTOLUMINESCENCE FROM SILICON NANO-PARTICLES SYNTHESIZED BY PULSED LASER ABLATION

We report on the synthesis and characterization of silicon nanoparticles by ablating silicon wafer in an ambient atmosphere of helium at 1 Torr. The mean cluster size ranging from 1.8 nm to 4.4 nm deposited on silicon substrate at room temperature is observed to depend on the laser fluence. The size of the nanoparticles decreases with laser fluence. Photoluminescence of the deposited films using Nd:YAG laser and Ar+ ion laser at 355 nm and 457.9 nm respectively shows emission peaks at 1.7, 2.2, and 2.7 eV. The luminescence peak at 2.2 eV and 2.7 eV are attributed to oxygen related impurities and the peak at 1.7 eV is attributed to quantum confinement.