Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Poster Wednesday: Plasmonics and Nanooptics 2

O 59.5: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P4

Near-field optical investigation of few layer graphene — •Lina Jäckering, Konstantin Wirth, Christian Justus, and Thomas Taubner — I. Institute of Physics (IA), RWTH Aachen University

Few layer graphene (FLG) samples usually consist of various stacking orders, which show different optical and electronical properties. Direct imaging and characterization of stacking domains in FLG samples can be done with scattering scanning near-field optical microscopy (s-SNOM) [1]. S-SNOM is outstanding for its nanoscale resolution of about 20 nm and its capability to image buried structures [2]. Thus, it allows to characterize encapsulated FLG samples as they are used in transport devices. Previous s-SNOM investigations focussed on the excitation of free charge carriers in FLG at about 0.1 eV [3,4]. Recently, FLG stackings have been identified by exciting interband transitions (0.27−0.56 eV) [1,5]. Interband resonances of FLG have only been measured at punctual energies or small energy regimes. Here, we investigate trilayer graphene and bilayer graphene in the spectral range of 0.27−0.9 eV, providing a deeper understanding of their near-field optical response, particularly of their interband resonance. Furthermore, we identify different stacking domains in FLG samples encapsulated in hexagonal boron nitride. Our findings provide a promising technique to select stacking domains for fabrication of transport devices.
1. Kim et al., ACS Nano, 9, 7 (2005); 2. Jeong et al., Nanoscale, 9, 12 (2017); 3. Fei et al., Nature 487, 82 (2012); 4. Jiang et al., Nat. Mater. 15, 840 (2016); 5. Wirth et al., arXiv: 2203.07971v1 (2022)