In-situ Raman spectroscopy and laser-induced fluorescence during laser chemical vapor precipitation of silicon nanoparticles

Abstract: Raman scattering in combination with laser-induced fluorescence (LIF) has been used to identify molecules and intermediates during the nucleation and growth of nanosized silicon particles by CO, laser excitation of silane. Upon switching on the CO, laser, the silane Raman peak height decreases due to a decrease in species number density and LIF peaks emerge due to presence of SiH, radicals. The dissociation temperature has been determined inside the reaction zone and a value of 605 K is obtained. The nucleation and growth mechanism starts with the insertion of the SiH, radicals into the Si-H bond of silane which is demonstrated by the formation of disilane. Amorphous nanosized silicon particles are obtained at reactor pressures of 50 torr and are collected on a cold finger