Thermally activated charge transport in modified tetragonal zirconia thin films prepared by sol-gel method

Films of Sn-doped ZrO2 were prepared using the sol-gel based dip-coating technique. The X-ray diffraction patterns showed a tetragonal structure with a preferential orientation along the (111) plane. The average grain size of the samples varies from 9.53 to 12.64 nm. Thermal analysis revealed endothermic peaks in the range 84-90 degrees C and exothermic peaks appearing in the range 489-531 degrees C. Fourier transform infrared (FTIR) spectra depicted bands located at 612 and 736 cm(-1), which are attributed to stretching mode and asymmetric vibrations of Zr-O and O-Zr-O bonds respectively. All films exhibited high transmittance in the visible range above 60% and the optical band gap (E-g) decreases from 4.085 to 4.061 eV. The impedance measurements show that the equivalent circuit of the samples is an RpCp where C-p is the capacitance of the layer and R-p its resistance. The electrical conductivity was found to follows an Arrhenius law with two activation energies. (c) 2018 The Japan Society of Applied Physics