Laser ablation deposition of silicon nanostructures

Pulsed laser deposition with an off-axis geometry in a low-pressure argon ambient was used to produce films of nanosized silicon clusters or crystallites. Size selection was achieved by the distance of the deposit from the target. The local film structure and the crystallite size of the films were studied as a function of the distance from the target using micro-Raman spectroscopy. The nanocrystal size on the off-axis placed substrate varied in the range 1...5 nm, increasing with increasing distance from the target; this made it possible to achieve size selection of the nanocrystals. The surface morphology of the deposits was studied using scanning electron microscopy. Room temperature photoluminescence of the samples with 514.5 nm excitation was rather weak. Silicon 2p core photoelectron spectra showed the existence of a silicon dioxide layer on the surface of the nanoparticles.