Tuning the charge carrier density of two-dimensional (2D) materials by incorporating dopants into the crystal lattice is a challenging task. An attractive alternative is the surface transfer doping by adsorption of molecules on 2D crystals, which can lead to ordered molecular arrays. However, such systems, demonstrated in ultra-high vacuum conditions (UHV), are often unstable in ambient conditions. Here we show that air-stable doping of epitaxial graphene on SiC—achieved by spin-coating deposition of 2,3,5,6-tetrafluoro-tetracyano-quino-dimethane (F4TCNQ) incorporated in poly(methyl-methacrylate)—proceeds via the spontaneous accumulation of dopants at the graphene-polymer interface and by the formation of a charge-transfer complex that yields low-disorder, charge-neutral, large-area graphene with carrier mobilities ~70 000 cm2 V−1 s−1 at cryogenic temperatures. The assembly of dopants on 2D materials assisted by a polymer matrix, demonstrated by spin-coating wafer-scale substrates in ambient conditions, opens up a scalable technological route toward expanding the functionality of 2D materials.
Uniform doping of graphene close to the Dirac point by polymer-assisted assembly of molecular dopants / He, Hans; Ho Kim, Kyung; Danilov, Andrey; Montemurro, Domenico; Yu, Liyang; Woo Park, Yung; Lombardi, Floriana; Bauch, Thilo; Moth-Poulsen, Kasper; Iakimov, Tihomir; Yakimova, Rositsa; Malmberg, Per; Müller, Christian; Kubatkin, Sergey; Lara-Avila, Samuel. - In: NATURE COMMUNICATIONS. - ISSN 2041-1723. - 9:3956(2018). [10.1038/s41467-018-06352-5]
Uniform doping of graphene close to the Dirac point by polymer-assisted assembly of molecular dopants
Domenico MontemurroMembro del Collaboration Group
;
2018
Abstract
Tuning the charge carrier density of two-dimensional (2D) materials by incorporating dopants into the crystal lattice is a challenging task. An attractive alternative is the surface transfer doping by adsorption of molecules on 2D crystals, which can lead to ordered molecular arrays. However, such systems, demonstrated in ultra-high vacuum conditions (UHV), are often unstable in ambient conditions. Here we show that air-stable doping of epitaxial graphene on SiC—achieved by spin-coating deposition of 2,3,5,6-tetrafluoro-tetracyano-quino-dimethane (F4TCNQ) incorporated in poly(methyl-methacrylate)—proceeds via the spontaneous accumulation of dopants at the graphene-polymer interface and by the formation of a charge-transfer complex that yields low-disorder, charge-neutral, large-area graphene with carrier mobilities ~70 000 cm2 V−1 s−1 at cryogenic temperatures. The assembly of dopants on 2D materials assisted by a polymer matrix, demonstrated by spin-coating wafer-scale substrates in ambient conditions, opens up a scalable technological route toward expanding the functionality of 2D materials.File | Dimensione | Formato | |
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