Effect of Fe Doping on Structural and Electrical Properties of Nanocrystalline ZnO Thin Films Prepared by Sol-Gel Dip Coating Technique

Nanocrystalline Fe-doped ZnO thin films were prepared by the sol-gel dip coating (SGDC) technique on quartz class substrate and annealed at 800 degrees C. The nanostructures, surface morphology, optical and electrical properties of these films were then characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption measurements and d.c. two-probe, respectively. The XRD spectrum shows ZnO thin film exhibits wurtzite crystal structure which is not affected by Fe doping. SEM images reveal reduction in crystallite size and quality with increase in Fe content. Optical studies indicated a reduction in band gap with increase in Fe content from 3.34 eV to 3.18 eV. The DC electrical measurements were carried out in the temperature range 300-500 K and it was found that increase in sample temperature gradually increased conductivity, ascertaining the semiconducting behaviour of these films, while the room temperature electrical measurements showed that the conductivity reduced with increase in Fe-doping.