Analysis of tem image contrast of quantum-dot semiconductor clusters in glasses

Nanometre-size semiconductor clusters trapped in glass matrices represent a novel class of nonlinear optical materials. Microstructural characterization of these materials by conventional and high-resolution transmission electron microscopy (TEM and HRTEM) shows the sensitivity of bright-field image contrast to the nature of the specific II-VI semiconductors (CdS, CdSe) precipitated in the glass matrices. An analysis based on electron-scattering intensity and structure-factor calculations is presented to account for the quality of TEM and HRTEM images observed for CdS- and CdSe-containing quantum-dot glasses.