Frequency dependence of ultrahigh dielectric constant of novel synthesized SnO2 nanoparticles thick films

In this work, the electric and dielectric properties of nanocrystalline SnO2 thick films were studied using ac impedance spectroscopy under different conditions through capacitance-frequency measurements in frequency range from 1 Hz to 1 MHz and bias voltage range from 0 V to 2 V. Results showed that dielectric constant (epsilon'), dielectric loss (epsilon ''), loss tangent (tan delta), ac electrical conductivity (sigma) and the electric modulus (M) are strongly frequency dependent. A decrease in frequency accompanied with an increase in epsilon' and epsilon '' values. Whereas, ac electrical conductivity (sigma), real (M-vertical bar) and imaginary parts of electric modulus (M-parallel to) values are increased with frequency increasing. A comparative study showed that our prepared thick films have greater dielectric value than that of the reported data; hence can be used them as ultrahigh dielectric materials. (C) 2010 Elsevier B.V. All rights reserved.