Materials Research Bulletin, Vol.46, No.8, 1276-1282, 2011
Solution precursor plasma deposition of nanostructured ZnO coatings
Zinc oxide (ZnO) is a wide band gap semiconducting material that has various applications including optical, electronic, biomedical and corrosion protection. It is usually synthesized via processing routes, such as vapor deposition techniques, sol-gel, spray pyrolysis and thermal spray of pre-synthesized ZnO powders. Cheaper and faster synthesis techniques are of technological importance due to increased demand in alternative energy applications. Here, we report synthesis of nanostructured ZnO coatings directly from a solution precursor in a single step using plasma spray technique. Nanostructured ZnO coatings were deposited from the solution precursor prepared using zinc acetate and water/isopropanol. An axial liquid atomizer was employed in a DC plasma spray torch to create fine droplets of precursor for faster thermal treatment in the plasma plume to form ZnO. Microstructures of coatings revealed ultrafine particulate agglomerates. X-ray diffraction confirmed polycrystalline nature and hexagonal Wurtzite crystal structure of the coatings. Transmission electron microscopy studies showed fine grains in the range of 10-40 nm. Observed optical transmittance (similar to 65-80%) and reflectivity (similar to 65-70%) in the visible spectrum, and electrical resistivity (48.5-50.1 m Omega cm) of ZnO coatings are attributed to ultrafine particulate morphology of the coatings. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords:Electronic materials;Nanostructures;Plasma deposition;Electrical properties;Optical properties