Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 44: Organic semiconductors I

HL 44.3: Talk

Thursday, March 26, 2009, 11:15–11:30, POT 51

Potential Measurements in the channel of organic field-effect transistors in top gate geometry — •Richa Sharma, Benedikt Gburek, Torsten Balster, and Veit Wagner — Jacobs University Bremen, Bremen, Germany

It has been found that the ordering of the semiconductor adjacent to the dielectric interface, where charge transport takes place, is crucial. Additional information on charge transport by measuring the voltage distribution over the channel can be obtained. This is not trivial in top-gate geometry due to the buried semiconductor layer. To enable potential measurements in this geometry, source and drain electrodes along with two sense fingers are patterned in the channel by optical lithography. In the experiment the drain current along with the potential values at the sense fingers are recorded simultaneously during drain and gate voltage variations. Model simulations of the transistor yielding current and potential values are compared to the experimentally obtained values. The measured voltage distributions show considerable deviations from the calculated values obtained by the gradual channel approximation. These deviations are mainly attributed to contact effects and major modifications of the voltage distribution in the channel in the sub-threshold regime.