A novel method for production of ultra-fine particles has been developed where the laser-ablated particles are efficiently collected to the target. When Si3N4 sintered ceramic is irradiated by KrF excimer laser, ablated silicon particles of diameters of 5 ∼ 15 nm are deposited to the target surface without any loss at ambient pressures between 10 ∼ 100 torr in Ar, O2, N2 and air. The radial extent of the particle deposition is proportional to the radius of the blast wave R developed in laser ablation given by R = (E/P)1/3 where E is laser energy and P pressure of the ambient gas, suggesting that the formation and deposition of the ultra-fine particles are closely related with the blast wave generated in the laser ablation.
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