COMPLEX IMPEDANCE SPECTROSCOPY OF THE INTERFACE BETWEEN ALUMINIUM AND EMERALDINE BASE POLYANILINE

Abstract

Emeraldine base poly aniline (PANI) forms semiconducting organic solid films when spin coated from xylene solution. An interface between aluminium contacts to emeraldine base polyaniline films were studied using complex impedance spectroscopy and current-voltage characteristics measurements. The current density-voltage curve is asymmetric and non-ohmic and shows Schottky barrier type rectification. The complex impedance spectra are semi-circles which reveal the existence of a region depleted of mobile charge carriers. It is modelled by an equivalent circuit consisting of one parallel RC circuit. The depletion region strongly depends on externally applied bias voltage, rendering very high impedance when a reverse bias voltage is applied.