Electrochemical deposition of ZnO nanowire arrays with tailored dimensions

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 621; no. 2; pp. 171 - 177
• Main Authors: Elias, J., Tena-Zaera, R., Lévy-Clément, C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-09-2008; Elsevier Science
• Subjects: Chemistry; Electrochemical deposition; Electrochemistry; Electrodeposition; Exact sciences and technology; General and physical chemistry; Growth mechanisms; Study of interfaces; ZnO nanowire arrays; Electrochemical deposition; ZnO nanowire arrays; Growth mechanisms; Scanning electron microscopy; Zinc II Chlorides; Zinc Oxides; X ray diffraction; Surface structure; Array; Transmission electron microscopy; Morphology; Growth mechanism; Electrodeposition; Potassium Chlorides; Nanowires; Aqueous solution; Dissolved oxygen; Electrochemical reaction
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2007.09.015

A study about the growth mechanism of ZnO nanowires electrodeposited from the reduction of dissolved molecular oxygen in zinc chloride solutions was reported. It was found that the ZnCl
2 concentration is a major parameter to control the dimensions of ZnO nanowires. Mean nanowire diameters from 25 to 80
nm were obtained by only modifying the ZnCl
2 concentration. No significant increase of the nanowire diameter was observed for the charge densities analyzed (2–70
C/cm
2), suggesting that the lateral growth took place only during the first growth stages. The internal structure of ZnO favored the anisotropic growth along the [0
0
0
1] direction of ZnO crystals. During the first growth stage, pyramidal crystals grew from the ZnO nanocrystals of the ZnO buffer layer, leading to the formation of rods and then nanowires. The electrochemical conditions used in the paper resulted in a relatively fast electrochemical reduction of O
2 in comparison to the diffusion of Zn
2+ to the cathode. Consequently, ZnO was formed only at the tips of the vertical cylindrical crystals, quenching their lateral growth. Transmission Electron Microscopy revealed that the obtained ZnO nanowires were single crystals, irrespective of [ZnCl
2], showing the great potential of this approach to obtain ZnO single crystal nanowire arrays with tailored dimensions.