Impedance studies of Sb doped SnO 2 thin film prepared by sol gel process

Abstract

Antimony-doped tin oxide thin films have a range of technological applications as conductive coatings, and sol–gel processing seems to offer some advantages over other coating techniques. In this study antimony-doped tin oxide (ATO) thin films have been prepared by the sol–gel dip-coating (SGDC) process, using tin (II) chloride dehydrate (SnCl 2, 2H 2O) and antimony (III) chloride (SbCl 3) as host and dopant precursors respectively. The structure of the (ATO) powders was analysed by X-ray diffraction (XRD) and the microstructure of the thin films by atomic force microscopy (AFM). These investigations show that the structure is tetragonal rutile type and that an increase in Sb-doping decreases the crystallite size of the (ATO) particles. To analyze the impedance spectroscopy data, the Nyquist ( Z″ vs . Z′) plots as well as the representation of imaginary ( Z″) and real ( Z′) parts of impedance vs. frequency were used. The Nyquist plots suggest that only the grain boundaries are responsible in the conduction mechanism of the material. From the variation of lnσ vs. inverse of absolute T we have deduced the activation energy found to be 0.87 eV.