• Iakimov, Tihomir
• Bauch, Thilo
• Yakimova, Rositsa
• Malmberg, Per
• Lara-Avila, Samuel
• Moth-Poulsen, Kasper
• Kubatkin, Sergey
• Kim, Kyung Ho
• Park, Yung Woo
• Montemurro, Domenico
• Lombardi, Floriana
• He, Hans
• Müller, Christian
• Danilov, Andrey

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 graphene with carrier mobilities ~70,000 cm2/Vs 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 towards expanding the functionality of 2D materials.

Topics

• Deposition
• density
• impedance spectroscopy
• surface
• polymer
• two-dimensional
• crystalline lattice
• spin coating