Electronic properties of poly[3-(2”,5”-diheptyloxyphenyl)-2,2'-bithiophene]/Al junctions

Abstract

Junctions between a single layer of Poly[3-(2”,5”-diheptyloxyphenyl)-2,2'-bithiophene] and aluminium are studied by means of current–voltage and capacitance-voltage characteristics, and complex impedance spectroscopy. The results indicate the formation of a Schottky barrier type at Poly[3-(2”,5”-diheptyloxyphenyl)-2,2'-bithiophene]/Al interface. Parameters such as the reverse saturation current, the barrier height and the ideality factor are extracted from the I-V curves. The Cole–Cole plots of complex impedance spectroscopy reveal part of a single semicircle, which can be modeled as a single parallel RC circuit. This suggests that the device is a metal-semiconductor (M-S) type. Capacitance per unit area as well as the width of the depletion layer are obtained from the complex impedance analysis. The built-in potential and the charge carrier concentration are also calculated from C-V curves.


Keywords/phrases: Electronic properties, built-in potential, depletion width, impedance spectroscopy, Schottky barrier


SINET: Ethiop. J. Sci Vol.26(1) 2003:11-16