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SYOF: Organische Festkörper
SYOF 5: Poster Session
SYOF 5.17: Poster
Tuesday, March 27, 2001, 17:00–19:00, Aula S3
Organic Mip-diodes by p-doping of amorphous wide-gap semiconductors: CV and impedance spectroscopy — •Jens Drechsel, Martin Pfeiffer, Xiang Zhou, Andreas Nollau, and Karl Leo — Institut für Angewandte Photophysik, TU Dresden, D-01062 Dresden, Germany
Organic thin film materials are widely investigated for applications in electronic and optoelectronic devices. For OLEDs with low operation voltage, controlled doping of the charge transport layers is particularly important. We have recently shown that starburst like amorphous materials (m-MTDATA) can be doped by strong molecular acceptors like F4-TCNQ (tetrafluoro- tetracyano-quinodimethane). These amorphous materials have the advantage that they are stable up to 100 ∘C and form smooth surfaces. Very well blocking Mip-type Schottky structures (rectification ratio 104 ... 105) allow to determine doping profiles using CV (capacity-voltage) spectroscopy. The interface between the doped and the undoped layer can be clearly seen as an abrupt change in the density of charged acceptors. Using frequency-dependent measurements, we identify the relevant electronic processes by comparison to a circuit model.