Langmuir-Blodgett films composed of size-quantized ZnO nanoparticles:: Fabrication and optical characterization

ZnO alcosols were synthesized by wet colloid chemical route. The particle diameters were found to be in the range of 3-6 mn studied by small angle X-ray scattering, transmission electron microscopy and UV-Vis spectroscopy. Mono- and multilayered films were prepared by Langmuir-Blodgett (LB) technique on fused silica and silicon supports. The films were studied by UV-Vis spectroscopy and scanning angle reflectometry (SAR). The experimentally determined optical band gap values (3.48-3.70 eV) revealed size-quantized ZnO particles in the LB films. After annealing the multilayers at 400 degrees C for 3 h, a nearly bulk-type semiconductor behaviour of particles was found (3.35-3.33 eV). SAR examinations, however, showed significant porosity (0.493) for the annealed films. (c) 2006 Elsevier B.V. All rights reserved.