Pure and porous silica xerogels doped with CdS nanocrystals have been
prepared by a sol-gel process. In order to determine parameters conven
ient for non-linear optical properties, particle size distributions we
re obtained by two complementary techniques: transmission electron mic
roscopy (conventional, CTEM, and high resolution, HRTEM) and small ang
le X-ray scattering (SAXS). Monolithic samples having CdO concentratio
ns varying from 5 to 20 wt % have been studied. Details are given of a
n image analysis technique used to study the CTEM micrographs.