A new approach for growing high-quality delafossite CuCoO2 films by spray pyrolysis through the optimization of the Cu/Co ratio

Abstract

Tremendous advancement in optoelectronic devices can be achieved by the improvement of high-performing p-type TCOs. Herein, we exhibit the manufacturing of the delafossite CuCoO2 tied to exceptional electrical and optical properties. A spray pyrolysis technique which is simple, uncomplicated, and adjustable was used to deposit the delafossite layers. We achieved homogeneous CuCoO2 films, high crystalline, and smooth surfaces. We investigate the role of the Cu/Co cation ratio and the annealing process on the prepared layers’ properties. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), atomic force microscopy (AFM), and UV spectroscopy are used in order to examine the deposited CuCoO2 films. We demonstrated the percentages of 30%, 40%, 50%, and 60% of copper which gave us pure samples without any impurities with good morphology and adequate structure shown by SEM, AFM, and TEM analyses, are the samples with the ratio [Cu: Co] = [2:3] and [1:1] that are equivalent to 40% and 50% of copper, respectively. Their band gaps are 2,5 eV and 2,4 eV with a transmission of 76% at 650 nm and 80% at 700 nm of wavelength. The achieved results are an original study comparing to the literature treating the effect of the precursors' ratio of Cu/Co and the temperature on the growth of delafossite CuCoO2 films with a low-cost technique.