CdS nanocrystalline films: Composition, surface, crystalline size, structural and optical absorption studies

Thin films of CdS nanoparticles of different crystalline sizes have been gr own by a precipitation technique and characterized by PIXE, RES, AFM, SEM, XRD and optical absorption studies. PIXE studies identify the presence of C d and S and indicate the absence of any foreign impurity even at ppm level, whereas RBS analysis identifies excess Cd in nano-CdS deposit. The bulk-Cd S gave stoichiometric CdS film. XRD analysis show presence of mixed cubic a nd hexagonal phases for bulk CdS films, whereas for nano-CdS samples predom inantly a cubic phase have been identified. AFM and SEM analysis show a rou gh and spongy morphology for all the samples which increases with increasin g crystalline size/thickness, From AFM and optical absorption studies, the geometry of the nanoparticles is predicted to be non-spherical. (C)1999 Act a Metallurgica Inc.