Nonlinear optical properties of plasma enhanced chemical vapour deposition grown silicon nanocrystals

We present a systematic study on the nonlinear optical properties of silicon nanocrystals (Si-nc) grown by plasma enhanced chemical vapour deposition (PECVD). The sign and magnitude of both real and imaginary parts of third-order nonlinear susceptibility chi((3)) of Si-nc are measured by Z-scan method. While the closed aperture Z-scan reveals a sign of positive nonlinearity, the open aperture measurements suggests a nonlinear absorption coefficients. Absolute values of X (3) are in the order of 10(-9) esu and show systematic correlation with the Si-nc size, due to quantum confinement related effects.