Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 26: Organic Semiconductors: Transistors and OLEDs (original: HL, joined by CPP, DS)

CPP 26.5: Talk

Tuesday, April 1, 2014, 15:00–15:15, POT 081

Contact Resistance Adjustment in Top-Contact Organic Field Effect Transistors by Localized Doping — •Ji-Ling Hou, Björn Lüssem, Daniel Kasemann, and Karl Leo — Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Str. 1, 01069 Dresden, Germany

The contact resistance between metal and organic interface is a key challenge for Organic Field-Effect Transistors (OFETs) when short channel lengths are used to achieve low-cost and high-frequency. In this study, bottom-gate top-contact organic field effect transistors (OFETs) with different thickness of the p-dopant 2,2-(perfluoronaphthalene-2,6-diylidene) (F6-TCNNQ) under Au electrodes were fabricated by orthogonal photolithography to further investigate their impact on contact resistance. Extracted by the transmission line method (TLM), contact resistance was found to be significantly reduced from 50 kOhm*cm to 10 kOhm*cm by adding a 1nm thin dopant layer. Doping leads to an improved injection at low gate voltages, while the contact resistance is also reduced in the undoped reference device due to the applied field at higher gate voltages. Finally, we conducted temperature dependent I-V measurement to study the change of contact resistance at lower temperature. The result shows an abrupt transition in the linear region between 220K and 240K, which gives a direct evidence and link between contact resistance and doping effect.