3D morphology of II-VI semiconductor nanocrystals grown in inverted micelles

Colloidal CdS nanocrystals have been elaborated by using a technique of the chemistry of colloids. Their mean size range between 3 and 10 nm. The 3D m orphology of the nanocrystals has been studied by using high-resolution tra nsmission electron microscopy (HRTEM). The method is based on the measureme nt of I-g,I-hr(r), the intensity of a family of g lattice fringes as a func tion of the position r(x,y) in the high-resolution electron micrograph, ass uming that I-g,I-hr increases monotonously as a function of the thickness t of the crystal along the electron beam. The range of thickness for the val idity of the method has been calculated in the frame of the dynamical theor y of electron diffraction. CdS colloids are mainly in the cubic structure o f blends-type (B) and a few of them are in the hexagonal structure of wurtz ite-type (W). In the cubic structure of B-type, the morphologies are found to be the octahedron and tetrahedron. The hexagonal structure of W-type, ha ve a platelet-like morphology with well-developed basal faces. (C) 1999 Els evier Science B.V. All rights reserved.