Charge Transport in UV-Oxidized Graphene and Its Dependence on the Extent of Oxidation.

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Title: Charge Transport in UV-Oxidized Graphene and Its Dependence on the Extent of Oxidation.
Authors: Lee, Hwa Yong1 (AUTHOR), Haidari, Mohd Musaib1 (AUTHOR), Kee, Eun Hee1 (AUTHOR), Choi, Jin Sik1 (AUTHOR), Park, Bae Ho1 (AUTHOR), Campbell, Eleanor E. B.2 (AUTHOR), Jhang, Sung Ho1 (AUTHOR) shjhang@konkuk.ac.kr
Source: Nanomaterials (2079-4991). Aug2022, Vol. 12 Issue 16, p2845-2845. 10p.
Subjects: Metal-insulator transitions, Graphene, Ballistic conduction, Hopping conduction, Oxidation, Transition metals
Abstract: Graphene oxides with different degrees of oxidation are prepared by controlling UV irradiation on graphene, and the charge transport and the evolution of the transport gap are investigated according to the extent of oxidation. With increasing oxygenous defect density n D , a transition from ballistic to diffusive conduction occurs at n D ≃ 10 12 cm − 2 and the transport gap grows in proportion to n D . Considering the potential fluctuation related to the e − h puddle, the bandgap of graphene oxide is deduced to be E g ≃ 30 n D (10 12 cm − 2) meV. The temperature dependence of conductivity showed metal–insulator transitions at n D ≃ 0.3 × 10 12 cm − 2 , consistent with Ioffe–Regel criterion. For graphene oxides at n D ≥ 4.9 × 10 12 cm − 2 , analysis indicated charge transport occurred via 2D variable range hopping conduction between localized s p 2 domain. Our work elucidates the transport mechanism at different extents of oxidation and supports the possibility of adjusting the bandgap with oxygen content. [ABSTRACT FROM AUTHOR]
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Abstract:Graphene oxides with different degrees of oxidation are prepared by controlling UV irradiation on graphene, and the charge transport and the evolution of the transport gap are investigated according to the extent of oxidation. With increasing oxygenous defect density n D , a transition from ballistic to diffusive conduction occurs at n D ≃ 10 12 cm − 2 and the transport gap grows in proportion to n D . Considering the potential fluctuation related to the e − h puddle, the bandgap of graphene oxide is deduced to be E g ≃ 30 n D (10 12 cm − 2) meV. The temperature dependence of conductivity showed metal–insulator transitions at n D ≃ 0.3 × 10 12 cm − 2 , consistent with Ioffe–Regel criterion. For graphene oxides at n D ≥ 4.9 × 10 12 cm − 2 , analysis indicated charge transport occurred via 2D variable range hopping conduction between localized s p 2 domain. Our work elucidates the transport mechanism at different extents of oxidation and supports the possibility of adjusting the bandgap with oxygen content. [ABSTRACT FROM AUTHOR]
ISSN:20794991
DOI:10.3390/nano12162845