Optical evaluation of silicon nanoparticles prepared by arc discharge method in liquid nitrogen

We have prepared silicon nanoparticles by an arc discharge method in liquid nitrogen. This system is easily adoptable in the preparation of large quantities of Si nanoparticles and has the potential for low-cost production. Etching Si nanoparticles with hydrofluoric acid reduced their size and passivated their surface such that they exhibited bright visible luminescence under UV illumination. The slow HF etching allows the formation of Si nanoparticles with a narrow size distribution. After etching, nanoparticles as small as 3-6 nm in diameter were obtained. Raman spectroscopy was used to determine the average diameter of Si nanoparticles during etching. The photoluminescence of Si nanoparticle was measured as a function of size and could be associated with a quantum confinement model.