Chemical bath deposition of cadmium sulphide on silicon nitride: Influence of surface treatment on film growth

Abstract

Nanoparticulate cadmium sulphide was grown by a chemical bath method on PECVD silicon nitride with various surface treatments. It was found that the packing density of the film increased in the order: untreated surface <mercaptopropyl-derivatised surface <ultra-thin (discontinuous) gold- or platinum-treated surface. This behaviour was rationalised by assuming that surface concentrations of Cd2+ or S2- could be increased over the bulk values by producing a surface with 'soft base' or 'soft acid' chemistry, respectively. Nanoparticle diameters were larger with ultra-thin platinum treatment than with gold. These observations may allow ordered arrays of cadmium sulphide nanoparticles to be prepared by a masking - gold seeding - bath deposition procedure. © 2006