Preparation of Ultrafine Si Powders from SiH_4 by Laser-induced Gas Phase Reaction

摘要

High quality ultrafine Si powders have been synthesized from SiH_4 by laser induced gas phase reaction. The powders produced under different synthesis conditions have mean particle size of 10—120 nm in diam. with narrow particle size distribution, and free of hard agglomerates. The powders are polycrystalline with the ratio of mean grain to particle diameter being between 0.3—0.7. The size of the powder increases with increasing laser power and reaction pressure, but decreases with increasing silane gas flow rate and the addition of Ar diluent. Grain sizes drop distinctly with the rise of the addition of Ar gas and laser power, but change little with the gas flow rate and reaction temperature. The formation of Si particles under different synthesis conditions is discussed.