Various methods of obtaining fine colloidal precipitates of cadmium sulfo-selenides
in Si02 gel matrices are described. These materials, which are of interest in opto-
electronic applications, can be prepared by diffusion of various reactants in wet gels.
The influence of different preparative parameters on the diffusion characteristics,
the possibility of obtaining distribution gradients and, in particular, the interest
of sonocatalysis (ultrasonic irradiation) are briefly presented.