Spin coating of transparent zinc oxide films using novel precursor

The coating of transparent ZnO films using zinc 2-ethylhexanoate [Zn(OOCH(C₂H₅)C₄H₉)₂] as a novel metal organic monomer is reported. Zinc 2-ethylhexanoate is liquid at room temperature and can be spin-coated on a flat substrate without precipitation of ZnO under ambient condition. The spin-coated films were heated at different temperatures to remove unwanted organic materials from the surface. It was found that transparent ZnO films could be produced on glass substrates at low heating temperature (~400 °C). The ZnO films produced using the new monomer were free of cracks and defects. Also the ZnO films produced using the new monomer have excellent optical transmittance, mechanical properties and small surface roughness. The surface morphology and degree of crystallinity of the films coated by the new monomer were compared with these properties of ZnO films produced using zinc acetate-based sol–gels. The results clearly indicate that the novel monomer is a potential precursor for coating transparent ZnO films at low temperatures.