Comparative study of ZnO nanostructures grown on silicon (1 0 0) and oxidized porous silicon substrates with and without Au catalyst by chemical vapor transport and condensation

ZnO tetrapods and rods were grown on silicon and thermally oxidized porous silicon substrates with and without Au catalyst layer by carbothermal reduction of ZnO powder through chemical vapor transport and condensation method (CVTC). Porous silicon was fabricated by electrochemical etching of silicon in HF solution. The effect of substrates on morphology, structure and photoluminescence spectra of ZnO nanostructures has been studied. The texture coefficient (TC) of each sample was calculated from XRD data that demonstrated random orientation of ZnO nanostructures on the oxidized porous silicon substrate. Moreover, TC indicates the effect of Au catalyst layer on formation of more highly oriented ZnO nanorods. The morphology of the samples was investigated by SEM which confirms formation of ZnO nanostructures on oxidized porous silicon substrates with and without catalyst. A blue-green emission has been observed in ZnO nanostructures grown on Si and the oxidized PS substrates without Au catalyst layer by PL measurements.