Morphology-dependent terahertz electrical conductivity of liquid-exfoliated graphite
Liquid-phase exfoliation (LPE) is a promising and scalable technique to produce low-cost dispersible nanosheets of graphene and nano-graphite for electronic, optoelectronics, and photonics applications. Fundamental information about how LPE affects the electrical properties is lacking. Here, a relat...
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Veröffentlicht in: | Optical materials express 2024-02, Vol.14 (2), p.505 |
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Sprache: | eng |
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Zusammenfassung: | Liquid-phase exfoliation (LPE) is a promising and scalable technique to
produce low-cost dispersible nanosheets of graphene and nano-graphite
for electronic, optoelectronics, and photonics applications.
Fundamental information about how LPE affects the electrical
properties is lacking. Here, a relationship is provided between the
morphology of nano-graphite flakes resulting from LPE and cascade
centrifugation to the charge-carrier transport properties. A range of
process parameters, such as centrifuge force and exfoliation solvent,
are employed, leading to a range of flake sizes. Morphology is
characterized by scanning electron microscopy, atomic force microscopy
and optical profilometry. Raman spectroscopy is used to confirm
morphology, crystallite size, and chemical properties. Terahertz
time-domain spectroscopy with a Drude-Smith conduction model provides
the charge-carrier concentration and scattering times from AC
conductivity. Carrier concentration increases with a reduction in
flake area, potentially resulting from the introduction of electronic
defect states at the edge of the nano-crystallites. Meanwhile, the
carrier scattering time decreases with decreased flake size, similarly
due to this self-doping that increases the carrier-carrier scattering.
The approach and results serve as a foundation for understanding the
processing-dependent electrical characteristics of LPE flakes and
nanosheets. |
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ISSN: | 2159-3930 2159-3930 |
DOI: | 10.1364/OME.513658 |