Electron and Hole Injection via Charge Transfer at the Topological Insulator Bi2–xSbxTe3–ySey–Organic Molecule Interface

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• 作者：Yoichi Tanabe ; Khuong Kim Huynh ; Ryo Nouchi ; Satoshi Heguri ; Gang Mu ; Jingtao Xu ; Hidekazu Shimotani ; Katsumi Tanigaki
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：February 20, 2014
• 年：2014
• 卷：118
• 期：7
• 页码：3533-3538
• 全文大小：289K
• ISSN：1932-7455

文摘

As a methodology for controlling the carrier transport of topological insulators (TIs), a flexible tuning in carrier number on the surface states (SSs) of three-dimensional TIs by surface modifications using organic molecules is described. The principle of the carrier tuning and its type conversion of TIs presented in this research are based on the charge transfer of holes or electrons at the TI鈥搊rganic molecule interface. When 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) as an electron acceptor or tetracyanoquinodimethane (TCNQ) as a donor is employed for n- and p-Bi_2鈥?i>xSb_xTe_3鈥?i>ySe_y (BSTS) single crystals, successful carrier conversion from n- to p-type and its reverse mode is demonstrated depending on the electron affinities of the molecules. The present method provides a nondestructive and efficient method for local tuning in carrier density of TIs and is useful for future applications.