METAL CHALCOGENIDE SEMICONDUCTORS GROWTH FROM AQUEOUS-SOLUTIONS

The chemical bath deposition of CdSe layers has been studied by means of quartz crystal microbalance (QCM) experiments, combined with TEM, H REM observations and EXAFS measurements. From mass vs time measurement s and the modelling of the time derivative, it is established that the nucleation/growth process occurs via two steps : the first one corres ponds to an instantaneous nucleation of cylindrical nuclei, with a 2D- growth until a complete coverage of the substrate; the second one cons ists of a 3D-instantaneous nucleation and growth process occuring on s ites randomly distributed on the evolving surface. The addition of sil icotungstic acid to the deposition bath is shown to influence the grow th kinetics of the CdSe deposit. Nanocrystalline deposits with the cub ic blende structure are obtained showing confinement effects. After th ermal treatment CdSe shows an hexagonal wurtzite structure with a larg e density of defects and the grain size is increased.