Preparation And Characterization Of Doped Zinc Oxide

Cathodic electrodeposition was used to prepare thin films of ZnO doped with Cd, from oxygenated KCl electrolyte containing ZnCl2 and CdCl2 in various molar ratios ranging from 0 mM to 5.0 mM each. Evidence for doping was obtained from X-ray powder diffraction, diffuse reflectance, chronopotentiometry, and X-ray photoelectron spectroscopy data. The Cd-doped ZnO samples showed a superior photoresponse relative to undoped ZnO. Cadmium- and indium-doped ZnO were prepared by combustion synthesis using CdCl2 and InCl3 as dopant precursors along with zinc nitrate and urea as the combustion mixture. The doped samples were compared and contrasted with undoped ZnO using scanning electron microscopy, X-ray powder diffraction, energy-dispersive X-ray analyses and X-ray photoelectron spectroscopy. Diffuse reflectance spectroscopy showed the optical bandgap of ZnO to shrink from 3.14 eV to 3.07 eV and 3.02 eV on Cd- and In-doping respectively. The doped samples showed an improved photoelectrochemical response relative to undoped ZnO over the wavelength range from ~300 nm to ~450 nm.