Synthesis and characterization of zinc oxide nanowires grown hydrothermally on glass substrate

We report the synthesis of ZnO nanowires grown on glass using a two-step process: (a) preparation of the seed layer, and (b) growth of the nanostructures. First step:solutions of zinc acetate dehydrate and 1-propanol of 10 mM concentrationwere spin coated on glass at 2000 rpm for 58 s. A seed layer was obtained after three layers of spin coating. Second step: vertical ZnO nanowires were grown by dipping the substrate in a 25 mMequimolarsolution of zinc nitrate hexahydrate and hexamethylenetetramine. Subsequently, films were thermally treated with a commercial microwave oven at different power settings (350 and 700 W) for 5, 20 and 35 min. The ZnO nanowires obtained were characterized optical and morphologically. Scanning electron microscopy analysis showed that the size of ZnO nanowires was less than 50 nm in diameter and around 500 nm in length. XRD patterns revealed that when low power in the microwave oven was utilized, the presence of Zn(OH)2 on the films is observed. The ZnO nanowires bandgap energy was obtained from optical transmission spectra.