Spatial distribution of damping coefficient of ablated particles prepared by pulsed laser ablation in Ar gas

The nanocrystalline silicon thin films were deposited on circular substrates with radiuses of 2.0, 2.5, 3.0, 3.5 and 4.0 cm by pulsed laser ablation in argon gas of 10 Pa at room temperature. The surface morphology and microscopic structure of the films were characterized by scanning electron microscopy, X-ray diffraction analysis and Raman spectroscopy. The results indicate that both the average size of Si nanoparticles and the damping coefficients of ablated particles are distributed symmetrically relative to the plume axis, and decrease with increasing the angle between substrate and plume axis. Meanwhile, the average size of Si nanoparticles and the damping coefficients of ablated particles decrease as the radius of circular substrate increases.