Preparation and optical properties of a SiO2 film containing In0.2Ga0.8As nanocrystals by radio-frequency magnetron co-sputtering

A SiO2 film containing In0.2Ga0.8As nanocrystals with size of about 3 nm wa s prepared by a radio frequency (r.f.) magnetron co-sputtering technique. T he microstructure of the film was characterized by X-ray diffraction, Raman spectra and transmission electron microscopy. Linear optical absorption wa s measured and discussed by an effective mass model. Non-linear optical abs orption and non-linear optical refraction were investigated by a Z-scan tec hnique using a single Gaussian beam of a He-Ne laser (632.8 nm). An enhance d third-order nonlinear optical absorption coefficient and non-linear optic al refractive index were achieved in the composite film and measured to be 0.67 cm/W and -2.7 x 10(-6) cm(2)/W. respectively. (C) 1998 Elsevier Scienc e S.A. All rights reserved.