Some aspects of pulsed laser deposition of Si nanocrystalline films

Abstract

Nanocrystalline silicon films were deposited by a picosecond laser ablation on different substrates in vacuum at room temperature. A nanocrystalline structure of the films was evidenced by atomic force microscopy (AFM), optical and Raman spectroscopies. A blue shift of the absorption edge was observed in optical absorption spectra, and a decrease of the optical phonon energy at the Brillouin zone centre was detected by Raman scattering. Early stages of nanocrystalline film formation on mica and HOPG substrates were studied by AFM. Mechanism of nanocrystal growth on substrate is discussed.

Nanosecond laser ablation and deposition of silicon

“…1), the nano-sized droplets were most likely amorphous, unlike the nanocrystallites deposited by using a picoseconds 355 nm laser at room temperature, vacuum and similar fluence [8]. In the report, nanocrystallites with an average size of 1.5 nm gave a Raman peak at 500 cm −1 with full width half maximum of ∼30 cm −1 , which was absent in our films.…”