Temperature impact on morphological evolution of ZnO and its consequent effect on physico-chemical properties

The temperature influenced morphology evolution and its effect on physico-chemical properties of ZnO thin films deposited onto glass substrates from alkaline environment, complexed via EDTA chelant are systematically studied. Temperature dependent growth mechanism model for change in microstructure is proposed. The physico-chemical properties of deposited films are studied by the analysis of structural, morphological, surface wettabillity, optical and electrical properties. Nanocrystalline ZnO thin films with hexagonal structure having mari-gold flowers and tetra pods like morphologies with optical band gaps 3.1 and 2.96 eV showed drastic surface wettabillity transformation from highly hydrophobic (142°) to superhydrophilic (<5°) behavior for bath placed at room temperature (300 K) and 333 K, respectively. The room temperature photoluminescence spectrum in the visible light region showed decreasing in intensity and electric resistivity measurement showed reduction in electrical resistivity from 10⁶ to 10⁴ Ω cm as consequence of increment in deposition temperature. The morphology evolution as impact of bath temperature can provide wide scope with significant change in physico-chemical properties of smart ZnO, which can be potentially tuned in many functional applications with feasibility.