Emergence of Photoswitchable States in a Graphene鈥揂zobenzene鈥揂u Platform

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• 作者：Emanuela Margapoti ; Philipp Strobel ; Mahmoud M. Asmar ; Max Seifert ; Juan Li ; Matthias Sachsenhauser ; 脰zlem Ceylan ; Carlos-Andres Palma ; Johannes V. Barth ; Jose A. Garrido ; Anna Cattani-Scholz ; Sergio E. Ulloa ; Jonathan J. Finley
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：December 10, 2014
• 年：2014
• 卷：14
• 期：12
• 页码：6823-6827
• 全文大小：295K
• ISSN：1530-6992

文摘

The perfect transmission of charge carriers through potential barriers in graphene (Klein tunneling) is a direct consequence of the Dirac equation that governs the low-energy carrier dynamics. As a result, localized states do not exist in unpatterned graphene, but quasibound states can occur for potentials with closed integrable dynamics. Here, we report the observation of resonance states in photoswitchable self-assembled molecular(SAM)-graphene hybrid. Conductive AFM measurements performed at room temperature reveal strong current resonances, the strength of which can be reversibly gated on- and off- by optically switching the molecular conformation of the mSAM. Comparisons of the voltage separation between current resonances (鈭?0鈥?20 mV) with solutions of the Dirac equation indicate that the radius of the gating potential is 鈭? 卤 2 nm with a strength 鈮?.5 eV. Our results and methods might provide a route toward optically programmable carrier dynamics and transport in graphene nanomaterials.

Keywords:

photochromatic molecules; graphene; atomic microscopy; doping