CONTROL OF SEMICONDUCTOR PARTICLE-SIZE IN SOL-GEL THIN-FILMS

Thin silica and silica-titania films containing CdS and PbS quantum si ze particles were obtained by separate preparation of the matrix and t he colloidal sols and successive mixing. Sulfide particles were obtain ed by reaction of metal acetates with thioacetamide and control of par ticle size was achieved by surface capping agents. Powders and thin fi lms deposited on soda-lime slides were prepared and characterized by X RD. Absorption spectra were recorded on films. The nonlinear refractiv e index was measured by an m-line technique on a CdS-doped sample. The nonlinear effect was found to be reversible and a n(2) value of -3 10 (-9) cm(2)/kW was measured.