Impedance characteristics of layer-by-layer electrostatic self-assembled films of Evans blue

Abstract

We have carried out impedance measurements of metal-insulator-metal structures based on thin films of evans blue deposited by the layer-by-layer electrostatic self-assembly (ESA) method. The results gave us a complete understanding of the electronic properties employed in layer-by-layer self-assembled thin films. It has been shown that a parallel capacitor-resistor (C_P-R_P) network can be considered to be equivalent in behaviour to such structures. Using conductive-system dispersion (CSD) model, the frequency dependence of the real and imaginary parts of conductivity has been investigated and the significant role played by the electrodes has been shown. All these studies have been made for devices with different concentrations of evans blue and under a dc bias voltage varying from 0 to 10 V in the frequency range of 10 Hz-1 MHz.