Control of interconnected ZnO nanowires to vertically aligned ZnO nanorod arrays by tailoring the underlying spray deposited ZnO seed layer

Morphology controlled, ZnO nano-wire/rod arrays were grown in two-step growth process, using spray pyrolysis deposited ZnO seed layer and subsequent nano-wire/rod growth via simple solution growth. We demonstrate that by tailoring the underlying ZnO seed layer, the morphology of ZnO nanoarrays can be tuned from interconnected nanowires to highly faceted, vertically aligned nanorod arrays. Deposition temperature of spray seed layers was varied from 350 °C to 550 °C. The diameter and alignment of the nanorod arrays found to increase with deposition temperature of seed layer. From the different morphology of nanostructural ZnO arrays, interconnected nanorod arrays have the super-hydrophobic nature with a water contact angle (CA) of 152° ± 2°, where as vertically aligned, prismatic, nanorod arrays show water CA of 119° ± 2.1°, due to reduction of air voids. The change in crystallite size and texture of spray deposited ZnO seed layers induced by variation in spray deposition temperature were responsible for the morphology, alignment, diameter control of ZnO nanoarrays.