Last modified: 2018-07-19
Abstract
Sara Bouzerara, Loubna Mentar.
Laboratoire de Chimie, Ingénierie Moléculaire et Nanostructures, Université Ferhat Abbas-
Sétif-1, 19000 Sétif, Algeria.
sarabouzrara@gmail.com.
ABSTRACT
Zinc oxide (ZnO) is a very important semiconductor with a direct wide band gap of ( Ì´ 3.37 eV) and larg exiton binding energy (60 meV) at room temperature [1], ZnO has a wide range of structural morphologies of such as nanobelts, nanorods [2,3] and nanowires[4]. Due to its important characteristics, ZnO is an ideal material for various applications in future electronic and photonic devices, such as solar cells, light emitting diodes and photoconductive sensors [5].
In this study, we reported the growth of ZnO nanowires directly on (ITO) coated glass substrates by electrodeposition route from aqueous solution under different thicknesses of ZnO seed layer ranging from 0 nm to 150 nm. The variation of the electrochemical, structural and optical properties of the ZnO nanowires grown at different thicknesses of ZnO seed layer were investigated. The Mott-Schottky analysis demonstrate an n-type semiconductor character for all the samples with a carrier density varied between 4,27 * 10 -20 and 9,27 í— 10 -20 cm-3 when the thickness of ZnO seed layer increases. From the electrochemical impedance spectroscopy (EIS), a low charge transfer resistance (Rct ) of 100,44 Ω was obtained. The XRD patterns indicated that ZnO nanowires crystallize in a hexagonal Wí¼rtzite structure along (002) crystallographic plane with a preferentially orientation along c-axis and an average crystallites size ranging from 95.816 to 97 .23 nm when the ZnO seed layer thickness increases. UV-Vis spectra showed a significant optical transmission (up to 70%), which increased with ZnO seed layer thickness. The energy band gap values (Eg) have been estimated to be between 3.3 and 3.13 eV.
References
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