Studies on the structural, morphological, optical and electrical properties of Al-doped ZnO nanorods prepared by electrochemical deposition

摘要

A study about the growth mechanism of zinc oxide (ZnO) nanorods and AI-doped zinc oxide (AZO) electrodeposited from the reduction of hydrogen peroxide in zinc chloride solutions was reported. The variations of the electrochemical, morphological, structural, optical and photoelectrochemical properties of the AZO thin films were investigated in terms of different Al concentration in the starting solution. X-ray diffraction spectra demonstrate that films crystalline with the Wurtzite structure with preferential (002) crystallographic orientation having c-axis perpendicular to the substrate. The AZO films obtained forms aligned hexagonal nanorods and depending on the increasing aluminium concentration, the surface morphologies of the films are changed. As Al concentration increased the optical band gap was also found to be increase from 331 to 3.45 eV and in the carrier densities from 1.06 x 10(18) to 2.91 x 10(18) cm(-3) are observed. The blue shift in the band gap energy was attributed to the Burstein-Moss effect. Changes in the photocurrent response are also discussed in the light of Al doping. The amplitude of the photocurrent generated increases steadily from undoped ZnO to the AZO film (2 at%) going from 21 to 58 mu A at 1.0 V. (C) 2015 Elsevier B.V. All rights reserved.