1999 Volume 27 Issue 10 Pages 670-675
We describe main features of ultrafine particles for the functional materials/devices and of physical vapor processing excited by a pulsed laser. Silicon ultrafine particles have been synthesized using the pulsed laser ablation in inert background gases. We have investigated the influence of the inert background gas pressures on transition from amorphous thin films to ultrafine particles. Furthermore, it has been clarified that there is a processing window of the inert background gas pressure in which the quantum confinement effects for carriers and phonons become apparent. Dual beam pulsed laser evaporation in inert background gases has been adopted for the synthesis of tungsten ultrafine particles. The ultrafine particles have been characterized with regard to crystal structures and agglomeration phenomena. Finally, we show results of size distribution measurements of the tungsten ultrafine particles in the formation fields by using a low pressure operating differential mobility analyzer.
