Stacking Structures of Few-Layer Graphene Revealed by Phase-Sensitive Infrared Nanoscopy

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• 作者：Deok-Soo Kim ; Hyuksang Kwon ; Alexey Yu. Nikitin ; Seongjin Ahn ; Luis Mart铆n-Moreno ; Francisco J. Garc铆a-Vidal ; Sunmin Ryu ; Hongki Min ; Zee Hwan Kim
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：July 28, 2015
• 年：2015
• 卷：9
• 期：7
• 页码：6765-6773
• 全文大小：700K
• ISSN：1936-086X

文摘

The stacking orders in few-layer graphene (FLG) strongly influences the electronic properties of the material. To explore the stacking-specific properties of FLG in detail, one needs powerful microscopy techniques that visualize stacking domains with sufficient spatial resolution. We demonstrate that infrared (IR) scattering scanning near-field optical microscopy (sSNOM) directly maps out the stacking domains of FLG with a nanometric resolution, based on the stacking-specific IR conductivities of FLG. The intensity and phase contrasts of sSNOM are compared with the sSNOM contrast model, which is based on the dipolar tip鈥搒ample coupling and the theoretical conductivity spectra of FLG, allowing a clear assignment of each FLG domain as Bernal, rhombohedral, or intermediate stacks for tri-, tetra-, and pentalayer graphene. The method offers 10鈥?00 times better spatial resolution than the far-field Raman and infrared spectroscopic methods, yet it allows far more experimental flexibility than the scanning tunneling microscopy and electron microscopy.