Photoelectrochemical and opto-electronic properties tuning of ZnO films: Effect of Cu doping content

In this work, copper (Cu) doped Zinc oxide thin films were prepared by co-precipitation and spin-coating method. Cu doping content was varied up to 5 at. %. Morphological and structural characteristics of the synthesized films were analyzed by Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD) and Raman Spectroscopy. XRD measurements demonstrated that films were polycrystalline with hexagonal phase. AFM investigations revealed uniform repartition of nanocrystallites. Optical band-gap has been tuned from 3.26 eV for undoped ZnO film to 3.19 eV for 5 at. % Cu doped one. Cu doping revealed significant effect on the optical properties, such as transmission and photoluminescence (PL). An optimum Cu doping of 1 at. % was reported to lead to the highest photoconduction sensitivity, photocurrent density and PL emission intensity.