Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 72: Poster Session: Si-based Photovoltaics / Inorganic Photovoltaics / Structure and Transport in Organic Photovoltaics / Organic Semiconductors

HL 72.28: Poster

Wednesday, March 28, 2012, 16:00–19:00, Poster D

Quantitative Kelvin probe force microscopy investigations of organic field-effect transistor channels — •Jan Murawski, Peter Milde, Moritz P. Hein, Merve Anderson, and Lukas Eng — TU Dresden, Institut für Angewandte Photophysik, George-Bähr-Str. 1, 01069 Dresden

Organic field-effect transistors (OFETs) are popular for several decades by now. Although expected to have a great impact on semiconductor electronics in the near future, OFETs still suffer from drawbacks such as high injection and extraction barriers at the electrodes and low charge carrier mobilities. Typically, only macroscopic values for these parameters are obtained, while the microscopic origins remain unknown.

In this contribution, we investigate channels of pentacene and poly[9,9-dio-ctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine] (TFB) based bottom-gate, bottom-contact OFETs using non-contact atomic force microscopy (nc-AFM) combined with frequency-modulated Kelvin probe force microscopy (FM-KPFM) [1] for mapping the surface potential with high sensitivity in ambient conditions. With this method we are able to visualize the local injection and extraction barriers, quantify their heights, and discover bottlenecks of charge transport within these devices.

[1] U. Zerweck et al., Accuracy and Resolution Limits of Kelvin Probe Force Microscopy. Phys. Rev. B 71:125424 (2005)