Structural, optical and electrical properties of Fe-doped SnO2 fabricated by sol–gel dip coating technique

Nanosized Fe3+-doped SnO2 thin film was prepared by the sol–gel dip coating (SGDC) technique on quartz class substrate and sintered at 800 °C. The microstructures, surface morphology and optical properties of these films were then characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption measurements, respectively. Electrical properties were analyzed, and resistivity, type and number of carrier concentration, Hall mobility measured as a function of Fe3+ doping and temperature. The XRD spectrum shows the decrease in peak heights as a result of Fe3+-doping while SEM images reveal reduction in crystallite size with increase in Fe3+ content. The optical studies showed a direct band gap reducing with increase in Fe3+-doping from 3.87 to 3.38 eV. From the electrical measurements, it was found that the resistivity initially increased with Fe3+-doping before reducing at higher doping level. Hall mobility measurements showed n-type conductivity at lower Fe3+-doping levels and p-type at higher levels. The increase in conductivity with temperature ascertained the semiconducting behavior of these films.