ZnO thin films: The effect of Co doping

n this work, undoped and Co doped ZnO semiconducting films which belong to Transparent Conducting Oxide (TCO) family have been obtained by Ultrasonic Spray Pyrolysis (USP) technique which is suitable for research/development studies and attracts attention among other production techniques with its properties such as being economic and easy to process, at 275±5 °C substrate temperature. Transmission and absorption spectra of the films have been taken to investigate the optical properties. From these spectra, optical properties such as reflection, refractive index, optical band gap and Urbach parameter have been determined. All of the films have been found to show n-type conductivity using Hot-probe technique. Temperature dependent (10-300K) conductivity variations have been studied to have information on electrical properties and activation and donor-like trap energies for each film have been determined using these plots. It has been determined from x-ray diffraction (XRD) patterns that all films have polycrystalline structure. Texture coefficient, full width half maximum and approximate grain size values for preferential orientations have been calculated. All of the films have been determined to show ferromagnetic property after the magnetization measurements made by Vibrating Sample Magnetometer (VSM) device. Scanning electron microscope (SEM) and Atomic Force Microscope (AFM) have been used to investigate whether the surfaces have a homogeneous distribution or not, and elemental analysis have been made by Energy Dispersive X-ray Spectroscopy (EDS). After all investigations, it has been concluded that Co doping has an important effect on the physical properties of ZnO films.