Frequency dependence of dielectric properties and electrical conductivity of Cu/nano-SnO2 thick film/Cu arrangement

The dielectric properties of Cu/nano-SnO2 thick film/Cu arrangement were studied by means of complex impedance spectroscopy and frequency dependence of capacitance measured from the impedance data at a range of frequency intervals between 1 Hz and 1 MHz with a voltage between 0 and 2 V. The frequency dependence of the dielectric constant ɛ′, dielectric loss ɛ″, loss tangent (tan δ), electric modulus M′ and M″ and AC electrical conductivity (σac) of the sandwich arrangement was subsequently investigated. Experimental results revealed that the aforementioned parameters have strong frequency dependence. The obtained values of ɛ′, ɛ″ showed increments with decreasing frequency. However, increasing frequency levels cause an increase in the AC electrical conductivity (σ), real and imaginary part of electric modulus. In addition to this, in order to gain an insight into the electric nature of Cu/nano-SnO2 thick film/Cu arrangement device, the Cole–Cole diagrams of the electric modulus were investigated at different voltages.

highlights
► The frequency dependence of the electrical measurements can be related to the microstructure of the polycrystalline material.
► Since RgCg # RgbCgb, a Maxwell Wagner relaxation occurs.
► The space charge polarization is revealed as a rapid rise in the dielectric constant at low frequencies.
► The semicircle at high and low frequencies can be assigned to charge transport within the grain and grain boundary effect, respectively.