Electrodeposition and impedance spectroscopy characterization of ZnO nanowire arrays

Abstract

An overview of the electrodeposition of ZnO nanowire arrays from the reduction of dissolved molecular oxygen in zinc chloride solutions was reported. In spite of the internal structure of ZnO which favours the anisotropic growth along the [0001] direction, the change in the local composition of the electrolyte around the nanowire during the electrodeposition was proposed as a major parameter to affect the nanowire growth mechanism. The influence of the ratio between the O2 reduction rate and the diffusion of Zn2+ to the cathode was emphasized. Due to the particular morphology of the nanowire arrays, no lateral growth was observed when the reduction of O2 was relatively fast, while the corresponding deposition efficiency was very low. The decrease of the O2 reduction rate resulted in an enhancement of the deposition efficiency. The highest efficiencies (40–55%) were attained by using high chloride concentrations ([KCl] = 3.4 M) resulting not only in an enhancement of the longitudinal growth, but also in a considerable lateral growth. The influence of the electrodeposition conditions on the donor density of ZnO nanowires was investigated by using electrochemical impedance spectroscopy. Donor densities from 5 × 1019 cm–3 to 3 × 1020 cm–3 were obtained for as deposited samples. They decreased to values in the range of 1017–1018 cm–3 after annealing in air (1 hour at 450 °C). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Functionalized polypyrrole nanotube arrays as electrochemical biosensor for the determination of copper ions

“…The ZnO NWs range from 380 nm to 410 nm in diameter and around 1.6 m in length. The top surface of the ZnO NWs becomes thinner and has a slightly hexagon facet, which is in good agreement with the morphology reported by Tena-Zaera and co-workers [24]. In order to obtain PPy-COOH NT arrays, PPy was firstly electropolymerized onto the surface of the ZnO NWs, achieving the ZnO/PPy hybrid arrays.…”

“…ZnO NW arrays were prepared by electrodeposition process according to the previous literature [24]. Prior to the electrodeposition, the indium-tin oxide (ITO) coated glass (1 cm × 5 cm) was cleaned in an ultrasonic bath for 20 min each in acetone, ethanol, and distilled water, respectively.…”

Cathodic electrochemical deposition of CuI from room temperature ionic liquid-based electrolytes

“…The cathodic electrodeposition has been shown as a versatile technique to obtain binary semiconductors such as metal oxides (e.g. ZnO [12], NiO [13]) and chalcogenides (e.g. CuS [14], CdSe [15], Bi 2 Te 3 [16]).…”

High-Efficiency Electrodeposition of Large Scale ZnO Nanorod Arrays for Thin Transparent Electrodes

“…The electrolyte D based on 0.1 M Zn(NO) 3 in DMSO and the chosen deposition parameters favor the ZnO NR deposition yielding the highest value reported till now in the matter. 30 SEM image of the ZnO NR obtained in stage IV of growth in organic media is presented in Figure 3a, after a partial dissolution of the alumina template. It is obvious from here that the ZnO NR growth followed the aspect ratio of the template used for the deposition.…”