Characterizing and controlling infrared phonon anomaly of bilayer graphene in optical-electrical force nanoscopy

We, for the first time, report the nanoscopic imaging study of anomalous infrared (IR) phonon enhancement of bilayer graphene, originated from the charge imbalance between the top and bottom layers, resulting in the enhancement of E 1u mode of bilayer graphene near 0.2 eV. We modified the multifrequ...

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Bibliographic Details
Published in:Light, science & applications science & applications, 2023-11, Vol.12 (1), p.281-281, Article 281
Main Authors: Jahng, Junghoon, Lee, Sunho, Hong, Seong-Gu, Lee, Chang Jun, Menabde, Sergey G., Jang, Min Seok, Kim, Dong-Hyun, Son, Jangyup, Lee, Eun Seong
Format: Article
Language:English
Subjects:
140/125
639/624/1107/510
639/624/1107/527/2257
639/624/400/1103
Atomic force microscopy
Electrostatic properties
Graphene
Lasers
Microwaves
Optical and Electronic Materials
Optical Devices
Optics
Photonics
Physics
Physics and Astronomy
RF and Optical Engineering
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Summary:We, for the first time, report the nanoscopic imaging study of anomalous infrared (IR) phonon enhancement of bilayer graphene, originated from the charge imbalance between the top and bottom layers, resulting in the enhancement of E 1u mode of bilayer graphene near 0.2 eV. We modified the multifrequency atomic force microscope platform to combine photo-induced force microscope with electrostatic/Kelvin probe force microscope constituting a novel hybrid nanoscale optical-electrical force imaging system. This enables to observe a correlation between the IR response, doping level, and topographic information of the graphene layers. Through the nanoscale spectroscopic image measurements, we demonstrate that the charge imbalance at the graphene interface can be controlled by chemical (doping effect via Redox mechanism) and mechanical (triboelectric effect by the doped cantilever) approaches. Moreover, we can also diagnosis the subsurface cracks on the stacked few-layer graphene at nanoscale, by monitoring the strain-induced IR phonon shift. Our approach provides new insights into the development of graphene-based electronic and photonic devices and their potential applications. Optical-electrical force nanoscopy. F dip , F es and F vdW are simultaneously applied and demodulated at the fundamental, second and third eigenmodes of a cantilever for PiFM, KPFM/EFM and topography images, respectively.
ISSN:2047-7538
2047-7538
DOI:10.1038/s41377-023-01320-1