A CO2 laser was used in a conventional plasma-enhanced chemical vapor deposition system to assist the decomposition of SiH4 molecules and also to separate the Si clusters from Si oxide matrix. Varying growth gas ratio caused the observed photoluminescence (PL) light emission to vary from 1.65eV to 1.92eV without post-annealing. A degradation of photoluminescence (PL) intensity by irradiating the sample with helium-cadmium (He-Cd) laser was observed. The dependence of PL degradation on long-term irradiation of He-Cd laser was investigated. Post-annealing in H2 could also help to increase the PL intensity plays by passivating the defect centers in as-deposited samples.