High structural order in thin films of the organic semiconductor diindenoperylene

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 approximate to16.5 Angstrom 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 rho(el.,DIP)(z). The mosaicity of the DIP thin films was obtained to be smaller than 0.01degrees. (C) 2002 American Institute of Physics.