Large surface relaxation in the organic semiconductor tetracene.
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 relaxation 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.
Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
Hazuki
H
Morisaki
RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
Takashi
T
Koretsune
Graduate School of Arts and Science, University of Tokyo, Meguro 153-8902, Japan.
Chisa
C
Hotta
Graduate School of Frontier Sciences, University Tokyo, Kashiwa 277-8561, Japan.
Jun
J
Takeya
Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
Tsuyoshi
T
Kimura
Division of Materials Physics, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531, Japan.
Yusuke
Y
Wakabayashi