Berlin 2008 – wissenschaftliches Programm

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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 3: Organic Devices I

SYSA 3.4: Vortrag

Dienstag, 26. Februar 2008, 15:30–15:45, H 2013

High resolution mapping of the electrostatic potential in organic thin film transistors by phase electrostatic force microscopy — •Paolo Annibale, Cristiano Albonetti, Pablo Stoliar, and Fabio Biscarini — CNR-Institute for the Study of Nanostructured Materials (ISMN), Bologna, Italy

We investigate by a scanning probe technique termed phase-electrostatic force microscopy the local electrostatic potential and its correlation to the morphology of the organic semiconductor layer in operating ultra-thin film pentacene field effect transistors.

In order to address experimentally the role of defects in the device performance it is necessary to map the local electrostatic potential in the semiconductor layer with a resolution comparable with that of the morphological features associated to them.

This technique yields a lateral resolution of about 60 nm, allowing us to visualize that the voltage drop across the transistor channel is step-wise. Spatially localized voltage drops, adding up to about 3/4 of the potential difference between source and drain, are clearly correlated to the morphological domain boundaries in the pentacene film.

This strongly supports and gives a direct evidence that in pentacene ultra-thin film transistors charge transport inside the channel is ultimately governed by domain boundaries.