  This work presents a cost-effective alternative technology for the formation
of nanostructured semiconductor materials for tunable light emitting devices.
CdS and ZnS semiconducting colloid nanoparticles coated with organic shell,
containing either SO3- or NH3+ groups, were deposited as thin films using the
technique of electrostatic self-assembly. The films produced were characterized
with UV-vis spectroscopy, spectroscopic ellipsometry and AFM. UV-vis spectra
show a substantial blue shift of the main absorption band of both CdS and ZnS
with respect to the bulk materials due to the phenomenon of quantum
confinement. The nanoparticles' radius of 1.8 nm, evaluated from the spectral
shift, corresponds well to the film thickness obtained by ellipsometry. AFM
shows the formation of larger aggregates of nanoparticles on solid surfaces.
  Keywords: CdS, ZnS, colloid nanoparticles, electrostatic self-assembly,
quantum confinement, ellipsometry, AFM
