Cadmium Sulfide and Zinc Sulfide Nanostructures Formed by Electrophoretic Deposition

Cadmium sulfide (CdS) and zinc sulfide (ZnS) nanostructures were formed by means of electrophoretic deposition of nanoparticles with mean diameter of 6 nm and 20 nm, respectively. Nanoparticles were prepared by a microwave assisted synthesis in aqueous dispersion and electrophoretically deposited on aluminum plates. CdS thin films and ZnS one-dimensional nanostructures were grown on the negative electrodes after 24 hours of electrophoretic deposition at direct current voltage. CdS and ZnS nanostructures were characterized by means of scanning electron (SEM) and atomic force (AFM) microscopies analysis. CdS thin films homogeneity can be tunable varying the strength of the applied electric field. Deposition at low electric field produces thin films with particles aggregates, whereas deposition at relative high electric field produces smoothed thin films. The one-dimensional nanostructure size can be also controlled by the electric field strength. Two different mechanisms are considered in order to describe the formation of the nanostructures: lyosphere distortion and thinning and subsequent dipole-dipole interactions phenomena are proposed as a possible mechanism of the one-dimensional nanostructures, and a mechanism considering pre-deposition interactions of the CdS nanoparticles is proposed for the CdS thin films formation.