Effect of Cu doping on the structural, optical and electrical properties of ZnO thin films grown by RF magnetron sputtering: application to solar photocatalysis

Abstract

RF sputtered undoped and Cu doped ZnO (CZO) thin films were deposited on unheated glass substrates using a mixed Cu2O and ZnO powders target at different Cu concentrations of 0, 1, 2, 3 and 4 wt.%. The effects of copper concentration on the structural, electrical, optical and photocatalytic properties of CZO films have been studied.From XRD and Raman spectroscopy studies, it was found that the deposited films were polycrystalline with a predominant hexagonal wurtzite structure along the c-axis perpendicular to the substrate surface. The presence of multiple interference fringes in the transmittance and reflectance spectra shows the good homogeneity of the films.All the films are highly transparent with transparency reaching 80% indicating the possibility to use these films as an optical window. The absorption tail gradually shifted towards a higher wavelength side, which resulted in the decrease of bandgap energy from 3.35 to 3.26 eV. All the sputtered films are highly conductive with a conductivity reaching 10 4 S.cm -1 .The effect of Cu-doping on the photocatalytic activity of ZnO thin films for the degradation of methylene blue (MB) dye was studied under sunlight irradiation and the results showed that the Cudoping provokes appreciable degradation of MB and reached a maximum for the 1 wt.% Cu doped ZnO film.

Highly transparent Bi4Ti3O12 thin-film electrodes for ferroelectric-enhanced photoelectrochemical processes

“…The presence of interference fringes in the transmittance curves conrms the uniformity in thickness, surface homogeneity, and the compact nature of the produced BiTO layers. [73][74][75][76] The extrapolated bandgap values for the BiTO electrodes were (3.56 ± 0.01) eV, (3.55 ± 0.01) eV, and (3.54 ± 0.01) eV for BITO 3, BiTO 5, and BiTO 7 respectively, which are in line with previously reported values for thin-lm BiTO compact layers. 60,72,77 Fig.…”

Enhancement in photo sensing and photocatalytic degradation activity of Cu doped ZnO nanoparticles prepared by co-precipitation method

“…In comparison to other semiconductors, ZnO are popular with their properties such as exciton binding energy (approximately 60 meV), band gap energy range from 3.10 to 3.37 eV (with respect to nanostructures), high oxidizing power, and high surface area which increases its activity for their application in various environmental applications [10]. In addition, ZnO is an ideal semiconductor due to its fascinating properties like low cost, non-toxicity, easy availability, and great chemical and mechanical stability [11]. Fast charge recombination rate, poor charge migration dramatically decreases the degrading efficiency of ZnO.…”