Large surface relaxation in the organic semiconductor tetracene

Hazuki Morisaki, Takashi Koretsune, Chisa Hotta, Jun Takeya, Tsuyoshi Kimura, Yusuke Wakabayashi
2014 Nature Communications  
Organic crystals are likely to have a large degree of structural relaxation near their surfaces because of the weak inter-molecular interactions. The design of organic field-effect transistors requires a detailed knowledge of the surface relaxation as the carriers usually transfer within the first few molecular layers at the semiconductor surfaces, and their transport properties reflect the structural changes through the transfer integral. Here, we report the direct observation of the surface
more » ... laxation of an organic semiconductor, a tetracene single crystal, by means of X-ray crystal truncation rod scattering measurements. A significant degree of surface relaxation is observed, taking place only in the first monolayer at the semiconductor surface. First principles calculations show that the resultant transfer integrals are completely different between the bulk and surface of the semiconductor.
doi:10.1038/ncomms6400 pmid:25377483 fatcat:xkecdaw3tzh2boiusazsakln3m