Growth of ZnO Nanostructures on Porous Silicon and Oxidized Porous Silicon Substrates

We have investigated an oxidation of substrate effect on structural morphology of zinc oxide (ZnO) rods. ZnO rods are grown on porous silicon (PS) and on thermally oxidized porous silicon substrates by carbothermal reduction of ZnO powder through chemical vapour transport and condensation. Porous silicon is fabricated by electrochemical etching of silicon in hydrofluoric acid solution. The effects of substrates on morphology and structure of ZnO nanostructures have been studied. The morphology of substrates is studied by atomic force microscopy in contact mode. The texture coefficient of each sample is calculated from X-ray diffraction data that demonstrate random orientation of ZnO rods on oxidized porous silicon substrate. The morphology of structures is investigated by scanning electron microscopy that confirms the surface roughness tends to increase the growth rate of ZnO rods on oxidized PS compared with porous silicon substrate. A green emission has been observed in ZnO structures grown on oxidized PS substrates by photoluminescence measurements.