Wang Binbin, Kim Sera, Zhai Tingting, Seok Jinbong, Yang Heejun, Salas-Montiel Rafael
Light, Nanomaterials, Nanotechnologies (L2n) Laboratory, CNRS ERL 7004, University of Technology of Troyes,10004 Troyes, France.
Key Laboratory of Light-Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China.
Nanotechnology. 2021 May 12;32(31). doi: 10.1088/1361-6528/abfb31.
Hexagonal boron nitride (hBN) is one of the most suitable 2D materials for supporting graphene in electronic devices, and it plays a fundamental role in screening out the effect of charge impurities in graphene in contrast to inhomogeneous supports such as silicon dioxide (SiO). Although many interesting surface science techniques such as scanning tunneling microscopy (STM) revealed dielectric screening by hBN and emergent physical phenomena were observed, STM is only appropriate for graphene electronics. In this paper, we demonstrate the dielectric screening by hBN in graphene integrated on a silicon photonic waveguide from the perspective of a near-field scanning optical microscopy (NSOM) and Raman spectroscopy. We found shifts in the Raman spectra and about three times lower slope decrease in the measured electric near-field amplitude for graphene on hBN relative to that for graphene on SiO. Based on finite-difference time-domain simulations, we confirm lower electric field slope and scattering rate in graphene on hBN, which implies dielectric screening, in agreement with the NSOM signal. Graphene on hBN integrated on silicon photonics can pave the way for high-performance hybrid graphene photonics.
六方氮化硼（hBN）是电子器件中支撑石墨烯最合适的二维材料之一，与诸如二氧化硅（SiO）等不均匀支撑物相比，它在屏蔽石墨烯中电荷杂质的影响方面起着至关重要的作用。尽管许多有趣的表面科学技术，如扫描隧道显微镜（STM）揭示了hBN的介电屏蔽并观察到了新出现的物理现象，但STM仅适用于石墨烯电子学。在本文中，我们从近场扫描光学显微镜（NSOM）和拉曼光谱的角度展示了hBN在集成于硅光子波导上的石墨烯中的介电屏蔽。我们发现，相对于在SiO上的石墨烯，hBN上的石墨烯的拉曼光谱发生了偏移，并且测量的电近场振幅的斜率降低了约三倍。基于时域有限差分模拟，我们证实了hBN上的石墨烯中较低的电场斜率和散射率，这意味着介电屏蔽，与NSOM信号一致。集成在硅光子学上的hBN上的石墨烯可为高性能混合石墨烯光子学铺平道路。
