Laser-driven synthesis of carbon and silicon clusters from gas-phase reactants

A newly developed technique is employed for the production of carbon and silicon cluster beams starting from gaseous compounds. It is based on the CO2-laser-induced decomposition of molecular gases containing carbon and silicon, such as C2H2 and SiH4, in a flow reactor. In order to decompose acetylene, SF6 is used as a sensitizer. By introducing a skimmer into the reaction zone, the generated silicon and carbon clusters are transferred to free molecular flow and analyzed with a time-of-flight mass spectrometer. It is shown that the technique can be efficiently employed to produce fullerenes C-60 and C-70 and, in the case of silicon, ultrapure nanosized particles of up to 3-nm diameter.