Preparation and Characterization of Cd/CdS-SiO2 Composite Film with High Third-order Optical Nonlinearity by Electrochemically Induced Sol-Gel Method

The sol was prepared with cadmium nitrate, thiourea and tetraethoxysilane as precursors by Sol-Gel method. The transparent film was prepared on ITO substrate by electrochemically induced Sol-Gel method using the as-prepared sol as electrolyte. SEM results showed that the film was made up of nano beams. While EDX results showed that the component elements of the film were Si, O, Cd, S and the atom ratio of Cd to S was more than 1. It could be inferred from both the EDX and cyclic voltammetry's results that the film composite was Cci/CdS-SiO2. Z-scan test results showed that the film had third-order optical nonlinearity with self defocusing nonlinear refraction and saturated absorption properties at the wavelength of 1064 nm. The third-order nonlinear optical susceptibility of films could reach 1.18 X 10(-14) (m/V)(2) to 1.39 X 10(-13) (m/V)(2) which demonstrated that the third-order nonlinear optical properties of these films were excellent. Further analysis showed that the content of CdS in the film remarkably influenced the optical nonlinearity.