Growth and characterization of vanadium doped ZnO thin films by ultrasonic spray pyrolysis technique

In this work, undoped and different proportions of vanadium (V) doped ZnO (3, 6, 9 and 12 at. %) thin films were deposited onto microscope glass substrates at 400 ? 5 ? C by using ultrasonic spray pyrolysis technique.Structural properties of the films were examined using x-ray diffraction technique and it was seen that all films have polycrystalline structure. Some structural parameters such as texture coefficient, the average grain size, dislocation density, lattice constant and unit cell volume of all films were calculated by XRD patterns. It was seen that all films have almost homogeneous surface datas obtained by means of atomic force microscope and scanning electron microscope. Elemental analysis of solid films was performed using energy dispersive x-ray spectroscopy.Optical transmittance, absorbance and reflectance spectra of deposited films were taken in the range of 300-900 nm and optical parameters such as optical transmissions, absorption coefficients, energy band gaps and Urbach parameters of the films were determined by using these spectra. As a result of investigations it has been evaluated that all films exhibit optical transmission around 70 at. %, and energy band gaps and Urbach parameters of the films were estimated to be ? 3,28 eV and between 66-92 meV, respectively. Two probe method have been used to examine electrical conduction mechanisms of films and electrical conductivity values were calculated for each film. Also it has been determined that all films have n-type conductivity by using hot probe technique. Magnetic properties of films were investigated by vibration sample magnetometer and it was seen that all deposited films exhibit ferromagnetic behavior at room temperature.All analysis revealed that incorporation of V has a significant effect on several physical properties of undoped ZnO films.