Templated one step electrodeposition of high aspect ratio n-type ZnO nanowire arrays

Abstract

High aspect ratio Zinc Oxide (ZnO) nanowires (NWs) were synthesized by template based one-step electrochemical deposition (OSECD) technique. The electro-reduction of hydroxide ions in the presence of Zn²⁺ ions within Zn(NO₃)₂ is involved in the growth of ultra thin NWs arrays. Field Emission Scanning Electron Microscopy (FESEM) images revealed that the growth rates of different crystal faces, (00001) and , were different at different deposition potential for the high aspect ratios ZnO NWs arrays. The n-type semiconductor conductivity of ZnO NWs was ascertained by a Hot-Probe approach. X-ray diffraction results demonstrated that the grown ZnO NWs had wurtzite crystal structure with unit cell parameters a=2.93 Å, c=5.45 Å and a deterioration of preferred (1 0 1) orientation is observed at more negative deposition potentials. Small angle X-ray scattering (SAXS) results evidenced that the NW arrays grown at −1.2 V have higher fraction of larger crystallites. Micro-Raman spectroscopy analysis showed that the variation in E₂ (high) vibration mode at 435 cm ⁻¹ is coupled with an increase in electro acceptor oxygen atoms incorporated within ZnO NWs at −1.2 V.