Frequency-dependent electrical conductivity of nanocrystalline SnO2

Nanocrystalline SnO2 with a crystallite size of 3–4 and 5–6 nm has been prepared by a sol-gel process in aqueous solution. Its ac electrical conductivity has been measured in dry air at a temperature of 200°C. The observed frequency dependence of its conductivity has been interpreted in terms of the random potential barrier model. The data obtained indicate that the transport properties of the material are dominated by hopping conduction through disordered crystallite boundaries.