Nonlinear Optical Properties of Silicon Nanocrystals Grown by Using a SiOx/SiO2 Superlattice Approach

The nonlinear optical properties have been studied using the Z-scan technique for silicon nanocrystals embedded in a SiO2 matrix formed by high-temperature annealing of SiOx/SiO2 superlattices grown by thermal evaporation. A mode-locked Ti:sapphire laser system producing 140-fs-long pulses at 800 nm was used as the optical source for the Z-scan measurements. The nonlinear refractive index and the nonlinear absorption coefficient of the silicon nanocrystals were found to be 1.2 × 10−13 cm2/W and 1.5 × 10−9 cm/W, respectively, and to be strongly enhanced compared to those of bulk silicon. Such enhancement of the nonlinear optical properties is considered to be due to the quantum confinement effect of silicon nanocrystals. KCI Citation Count: 0