Regensburg 2007 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices

SYOE 8: Poster Session SYOE

SYOE 8.86: Poster

Dienstag, 27. März 2007, 18:00–20:00, Poster B

Frequency response of transconductance on OFETs with different source/drain contacts — •Ingo Hörselmann, Andrei Herasimovich, and Susanne Scheinert — TU Ilmenau, PF, 98684 Ilmenau, Germany

We prepared organic field effect transistors with spin coated TPD(4M)-MEH-PPV as semiconductor material. Silanized silicon dioxide was used as gate insulator. The source and drain contacts were implemented in bottom contact (BOC) and top contact (TOC) design with different contact materials evaporated through a shadow mask.

The two transistor designs were investigated by static measurements. Only TOC structure transistors show a nonlinearity in the output characteristic at low drain voltages. Additional we measured the frequency response of the transconductance at different gate voltages in linear and saturation regime. In case of top contact structures the transconductance shows in the linear transistor regime an additional phase shift above the cut-off frequency. This phase shift was caused by the frequency dependency of gate-drain capacitance.

We compare the measurement results with two dimensional device simulations. The nonlinearity in the output characteristic and the phase shift in the transconductance can be caused by trap states and anisotropic mobility.