Frequency behavior and the Mott–Schottky analysis in poly(3-hexyl thiophene) metal–insulator–semiconductor diodes

Abstract

Metal–insulator–semiconductor diodes with poly(3-hexyl thiophene) as the semiconductor were characterized with impedance spectroscopy as a function of bias, frequency, and temperature. We show that the standard Mott–Schottky analysis gives unrealistic values for the dopant density in the semiconductor. From modeling of the data, we find that this is caused by the relaxation time of the semiconductor, which increases rapidly with decreasing temperature due to the thermally activated conductivity of the poly(3-hexyl thiophene).