Starting from the question, what fast electronic transport is based on, and why organic materials in general are more problematic in this respect than typical inorganic ones, methods are introduced that allow to measure the principal material property charge carrier mobility. Some representative experimental results are presented which prove that mobilities around 1–10 cm2/V s can be achieved at room temperature, and more than 100 cm2/V s at low temperature—but only if chemical purity and structural order can be brought to a very high level.

We report extraordinary structural order along the surface normal in thin films of the organic semiconductor diindenoperylene (DIP) deposited on silicon–dioxide surfaces. Cross-sectional transmission electron microscopy (TEM), noncontact atomic force microscopy (NC–AFM), as well as specular and diffuse x-ray scattering measurements were performed to characterize thin films of DIP. Individual monolayers of essentially upright-standing DIP molecules could be observed in the TEM images indicative of high structural order. NC–AFM images showed large terraces with monomolecular steps of ≈16.5 Å height. Specular DIP Bragg reflections up to high order with Laue oscillations confirmed the high structural order. A semi-kinematic fit to the data allowed a precise determination of the oscillatory DIP electron density ρel.,DIP(z). The mosaicity of the DIP thin films was obtained to be smaller than 0.01°.

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