Optical Properties of ZnO Powders Modified with ZnO Nanoparticles

Diffuse reflectance spectra (rho lambda) in the range of 0.2-2.5 mu m and their changes after modification of micron-sized zinc oxide mZnO powders with nZnO nanopowders of various concentrations have been investigated. A decrease in the reflection coefficient (rho) in the region of 0.40-1.0 mu m and its increase in the region of 1.0-2.5 mu m in modified mZnO/nZnO powders have been established. It is shown that a decrease in the reflection coefficient is determined by an increase in the concentration of intrinsic point defects. The increase in the reflection coefficient is determined by two factors: an increase in the concentration of free electrons and an increase in the scattering coefficient due to a change in the granulometric composition of the modified powders. A mechanism for the formation of granules in nanoparticle-modified powders has been proposed.