Formation mechanism and optical properties of nanocrystalline silicon in silicon oxide

Abstract

Silicon nanocrystals with diameters ranging from 1.5 to 3 nm were formed on silicon substrates by using a pulsed laser deposition (PLD) followed by annealing and oxidation. The optical and structural properties of the films have been investigated as a function of deposition temperature, annealing, and oxidation process. When the deposition temperature increased, photoluminescence intensity abruptly decreased and peaks showed redshift. Annealing process can reduce the number of defect centers. Oxidation has considerable effect upon the formation and isolation of the nanocrystals. These results suggest that the formation mechanism of Si nanocrystals by using PLD could be explained by three steps of growth, passivating defect centers, and isolation, sequentially.