Production of silicon containing particles by laser induced reaction of silane with methane, ethane and acetylene

Silicon containing ultrafine particles (Si and SiC) have been obtained by pulsed IR laser irradiation of gaseous SiH4/hydrocarbon (CH4, C2H6 and C2H2) mixtures. The chemical composition and structure of the powders formed were determined by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD) and I.R. and UV-v spectroscopy. The particles are small, uniform, loosely agglomerated spheres with a mean size of approximately 19 nm. To complete the characterisation of these ultrafine silicon-containing particles, the X-ray absorption spectra (XAS) were obtained using synchrotron radiation at the silicon absorption K-edge. We show that the use of pulsed laser radiation results in the generation of amorphous Si and crystalline SiC particles depending on the gas mixtue used, among other parameters such as composition of the mixture, laser fluence, pressure and number of laser pulses.