Effect of Zn2+ concentration on the zinc oxide properties prepared by electrochemical deposition

Abstract

In this work, ZnO nanostructures are electrodeposited on ITO conducting substrate prepared from chloride baths. The influence of concentration of Zn²⁺on the electrochemical characteristics has been studied using cyclic voltammetry (CV) and chronoamperometry (CA) techniques. The Mott–Schottky measurements demonstrate an n-type semiconductor character for all samples with a carrier density varying between 1.47×10¹⁸ cm⁻³ and 3.14×10¹⁸ cm⁻³. Scanning electron microscopy (SEM) show arrays of vertically aligned ZnO nanorods (NRs) with good homogeneity. X-ray diffraction spectra demonstrate that films crystalline with the Würtzite structure with preferential (002) crystallographic orientation having c-axis perpendicular to the substrate. The high optical properties of the ZnO NRs with a low density of deep defects was checked by UV-Vis transmittance analyses, the band gap energy of films varies between 3.3 and 3.4 eV with transparency around 80-90 %.