Effect of oxidizer on grain size and low temperature DC electrical conductivity of tin oxide nanomaterial synthesized by gel combustion method

Nanocrystalline Tin oxide material with different grain size was synthesized using gel combustion method by varying the fuel (C6H8O7) to oxidizer (HNO3) molar ratio by keeping the amount of fuel as constant. The prepared samples were characterized by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Analysis X-ray Spectroscopy (EDAX). The effect of fuel to oxidizer molar ratio in the gel combustion method was investigated by inspecting the grain size of nano SnO2 powder. The grain size was found to be reduced with the amount of oxidizer increases from 0 to 6 moles in the step of 2. The X-ray diffraction patterns of the calcined product showed the formation of high purity tetragonal tin (IV) oxide with the grain size in the range of 12 to 31 nm which was calculated by Scherer's formula. Molar ratio and temperature dependence of DC electrical conductivity of SnO2 nanomaterial was studied using Keithley source meter. DC electrical conductivity of SnO2 nanomaterial increases with the temperature from 80K to 300K. From the study it was observed that the DC electrical conductivity of SnO2 nanomaterial decreases with the grain size at constant temperature.