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 degrees 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. (C) 2011 Published by Elsevier Ltd.