To determinate the nucleation region of Si nanoparticles formed in gas phase, the single crystalline Si target with high resistivity was ablated by a XeCl excimer laser in pure Ar gas under the ambient pressure of 10Pa, and the nanocrystalline Si films were systemically deposited on pieces of glass or single crystalline (111) Si substrates lined up at a distance of 2.0cm under the plasma. The Raman and X-ray diffraction spectra, scanning electron microscope and atomic force microscope images of the films show that Si nanoparticles were formed on the pieces placed at horizontal distances 0.5 to 2.8cm from the target, the average size of Si nanoparticles monotonically decreased with the distance increasing. The region that Si nanoparticles form in gas phase was estimated on the basis of the PLA dynamics.

The single crystalline Si target with high resistivity was ablated by a XeCl excimer laser (laser fluence 4J/cm2, repetition rate 1Hz), and at the ambient pressure of 10Pa of pure Ar gas, the nanocrystalline silicon film was deposited on a glass or single crystalline (111) Si substrate located at a distance of 3cm from the Si target in 30 and 10min, respectively. The Raman and x-ray diffraction spectra of the film deposited on the glass substrate indicate the film is nanocrystalline, which means that it is composed of Si nanoparticles. Scanning electron microscopy of the film on the Si substrate shows that the film has the mosaic structure of Si nano-crystallites of uniform size. The photoluminescence peak wavelength is 599nm with full width at half maximum of 56nm, which is blue-shifted and narrower than that obtained in He gas.