Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 14: Poster I

HL 14.45: Poster

Monday, March 24, 2003, 17:00–19:30, HSZ/P2

Electro-absorption and internal electric field distribution in organic single layer devices — •Wenge guo, Jens Drechsel, Karin Schmidt, Michael Hoffmann, and Karl Leo — Institut fuer Angewandte Photophysik,TU-Dresden, George-baehr-strasse 1, 01069, Dresden

Quasi-1D organic crystals are attractive for device applications, because the generation and transport of charge carriers are expected to be favoured due to the strong inter-molecular interactions. Electro-absorption (EA) measurements on polycrystalline MePTCDI (N, N-dimethylperylene-3,4,9,10-dicarboximide) and PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) layers were performed to investigate the contribution of Charge-Transfer excitons. For the interpretation of the absolute amplitude of EA signals, the actual internal fields in the samples have to be clarified. We conduct current-voltage, capacitance-frequency and capacitance-voltage measurements on ITO/PTCDA /Au and ITO/MePTCDI/Au sandwich samples. Fresh samples in air show Schottky diode behaviour with clear space charge regions. In aged samples, space charge effects can be neglected and the amplitude of the EA signals suggests strong charge-transfer contributions. Keywords: Electro-absorption, PTCDA, MePTCDI,.