In-Plane Orientation Control of 2,7-Diphenyl[1]benzothieno[3,2-b][1]benzothiophene Monolayer on Bismuth-Terminated Si(111) Vicinal Surfaces with Wettability Optimization

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• 作者：Manabu Ohtomo ; Yuya Tsuchida ; Naoki Muraya ; Takashi Yanase ; Seiji Sakai ; Tetsu Yonezawa ; Taro Nagahama ; Tetsuya Hasegawa ; Toshihiro Shimada
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：June 6, 2013
• 年：2013
• 卷：117
• 期：22
• 页码：11555-11561
• 全文大小：454K
• 年卷期：v.117,no.22(June 6, 2013)
• ISSN：1932-7455

文摘

We report the in-plane orientation control of a high-mobility organic semiconductor: 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DPh-BTBT). As previously reported for the monolayer pentacene, it was revealed that bunched steps on the vicinal Si(111) with a bismuth termination break the surface 3-fold symmetry and reduce the multiple orientation of the DPh-BTBT grains into a quasi-single orientation. Interestingly, the critical step height necessary for the orientation control was higher than that of pentacene. We examined several mechanisms of orientation control and concluded that the facet nanostructure fabricated by step bunching works as an anisotropic template for the nucleation. We also show the wettability optimization of the bismuth-terminated silicon surface and show that the growth mode of DPh-BTBT is dependent on the surface nanostructure of Bi鈥揝i.