Compositionally complex zinc oxide (Cu_xCo_xMn_xMg_xNi_x)Zn_1-5xO thin films synthesized by spin coating technique with enhanced band gap and transparency

In this current research multiple elements i.e., Co, Mn, Mg, Cu, and Ni were doped to produce compositionally complex ZnO (CCZO) thin films which are denoted by (Cu_xCo_xMn_xMg_xNi_x)Zn_1-xO (where x = 0.02, 0.04, and 0.06). Spin coating technique and sol-gel method was used to prepare the pure ZnO and CCZO thin films. The structural properties of the prepared thin film samples were analyzed using X-ray Diffraction (XRD), where the morphological properties were revealed using Scanning Electron Microscopy (SEM), the elemental composition was determined using Energy-dispersive X-ray Spectroscopy (EDS), and finally the optical properties were studied using UV-Visible Spectroscopy analysis. From XRD analysis it was observed that ZnO could incorporate the mentioned elements to a high level of 30% without altering its crystal structure and emerging a new phase. The crystallite size increases from 36.90 nm to 41.36 nm for 10% doping followed by a decline to 28.64 nm and 26.05 nm for 20% and 30% doping respectively. The spherical particle-shaped morphology of pure ZnO thin film, revealed from SEM investigation changed to the wrinkle type after doping. The successful incorporation of the targeted elements in CCZO thin films was confirmed by the EDS analysis. The transparency of the fabricated CCZO thin films increases gradually in the visible wavelength region. The optical band gap of the pure ZnO thin film was found to be 3.27 eV which increases in CCZO thin films to around 3.38 eV for 30% doping.