ELECTRICAL CHARACTERIZATION OF GAP STATES IN A HIGHLY DOPED CONDUCTING OLIGOMER

The electrical characteristics of organic semiconducting devices are s trongly influenced by the presence of interface states, midgap states and trap states in the band gap of the semiconductor. Therefore, knowl edge of the density of states (DOS) in the band gap of the organic sem iconductor is important to characterize and improve future organic dev ices. In this paper we explore a method that is based on frequency-dep endent capacitance-voltage measurements on a highly doped In-thiophene Schottky diode. The obtained DOS of the highly doped thiophene clearl y contains structure, with a peak around 0.52 +/- 0.06 eV above the va lence band.