Effect of pH on the electrical properties and conducting mechanism of SnO2 nanoparticles

Semiconductor nanoparticles have attracted more interests because of their size-dependent optical and electrical properties. SnO2 is an oxygen-deficient n-type semiconductor with a wide band gap of 3.6 eV (300 K). It has many remarkable applications as sensors, catalysts, transparent conducting electrodes, anode material for rechargeable Li-ion batteries and optoelectronic devices. In the present work, the role of pH in determining the electrical and dielectric properties of SnO2 nanoparticles has been studied as a function of temperature ranging from Room temperature (RT) to 114 degrees C in the frequency range of 7 MHz to 50 mHz using impedance spectroscopic technique. The non linear behavior observed in the thermal dependence of the conductance of SnO2 nanoparticles is explained by means of the surface property of SnO2 nanoparticles where proton hopping mechanism is dealt with. Jonscher's power law has been fitted for the conductance spectra and the frequency exponent (s value) gives an insight about the ac conducting mechanism. The temperature dependence of electrical relaxation phenomenon in the material has been observed. The complex electric modulus analysis indicates the possibility of hopping conduction mechanism in the system with nonexponential type of conductivity relaxation.