PHOTOCONDUCTIVE AND SEMICONDUCTIVE PROPERTIES OF ALPHA-SEXITHIENYL

Photo- and dark conduction in alpha-sexithienyl (alpha-6T) is studied as a function of applied voltage and temperature. The results suggest that a single discrete trapping level is involved in the conduction pr ocess. From this study some transport parameters are evaluated. The de pendence of photocurrent on light intensity indicates that the carrier generation process is a one photon process and is trap limited. With increase of excitation light intensity, the recombination process chan ges from bimolecular to monomolecular. The dependence of the photocurr ent on wavelength indicates that the carrier generation process is ext rinsic in nature and that surface recombination is high for holes.