Nanosized semiconductors have been highly desirable as optoelectronic materials since the discovery of photoluminescence from porous nanostructured silicon. There are many investigations about visible light emission from nanostructured semiconductors, and several studies showed the size dependence of the photoluminescent and electronic property [1], [2]. In order to investigate the size effect of those optical properties of nanoparticles, the size-selection technique is important.

Size-selection of silicon nanoclusters has been carried out by crossing, an Ar molecular beam perpendicularly to the silicon cluster beam. The laser ablation in inert gas method was used for fabricating nanometer-sized silicon. Large size silicon clusters are produced by Nd:YAG laser irradiation of a silicon wafer which was rotating in ablation chamber under He-gas flow. Produced nanoparticles were extracted through a nozzle ( ϕ = 0.6 mm) to a differentially pumped chamber and then skimmed into a high vacuum chamber for size selection and deposition.