Optical Probing of the Electronic Interaction between Graphene and Hexagonal Boron Nitride

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• 作者：Gwanghyun Ahn ; Hye Ri Kim ; Taeg Yeoung Ko ; Kyoungjun Choi ; Kenji Watanabe ; Takashi Taniguchi ; Byung Hee Hong ; Sunmin Ryu
• 刊名：ACS Nano
• 出版年：2013
• 出版时间：February 26, 2013
• 年：2013
• 卷：7
• 期：2
• 页码：1533-1541
• 全文大小：503K
• 年卷期：v.7,no.2(February 26, 2013)
• ISSN：1936-086X

文摘

Even weak van der Waals (vdW) adhesion between two-dimensional solids may perturb their various materials properties owing to their low dimensionality. Although the electronic structure of graphene has been predicted to be modified by the vdW interaction with other materials, its optical characterization has not been successful. In this report, we demonstrate that Raman spectroscopy can be utilized to detect a few percent decrease in the Fermi velocity (v_F) of graphene caused by the vdW interaction with underlying hexagonal boron nitride (hBN). Our study also establishes Raman spectroscopic analysis which enables separation of the effects by the vdW interaction from those by mechanical strain or extra charge carriers. The analysis reveals that spectral features of graphene on hBN are mainly affected by change in v_F and mechanical strain but not by charge doping, unlike graphene supported on SiO₂ substrates. Graphene on hBN was also found to be less susceptible to thermally induced hole doping.

Keywords:

graphene; boron nitride; Raman spectroscopy; 2D band; electronic coupling