Formation and laser-induced-fluorescence study of SiO+ ions produced by laser ablation of Si in oxygen gas

Abstract

We have studied laser-induced-fluorescence (LIF) spectra of SiO+ produced by laser ablation of a Si wafer in oxygen ambient gas. Emission from neutral and ionic species of Si atoms and SiO molecules is also studied in the laser-induced plasma plume. The optimum oxygen pressure for the formation of molecular ions is found to be ∼120 mTorr. The rotational temperature of SiO+ ions shows rapid thermalization toward room temperature within 20 μs.