Electrical characterization of nanocrystalline titania—I: (Impedance spectroscopy studies between 300 K and 473 K)

The electrical properties of nanocrystalline titania with gold electrodes were characterized using impedance spectroscopy in the frequency range 10−2 to 106 Hz and temperature range 300 K to 500 K. An attempt has been made to correlate the microstructural properties of these specimens to the electrical response of the material over the different ranges of temperatures. The results indicate that the conductivity of nanocrystalline titania is dependent on the porosity, grain size, and grain boundaries. The impedance and polarization behavior of the samples, especially at the electrodes, is also affected by the humidity. The electrical behavior of the nanocrystalline material makes it a candidate for use as a low temperature gas sensor.