Ferroelectrically driven spatial carrier density modulation in graphene

• Published in: Nature communications 2015-01, Vol.6 (1), p.6136-6136, Article 6136
• Main Authors: Baeumer, Christoph, Saldana-Greco, Diomedes, Martirez, John Mark P., Rappe, Andrew M., Shim, Moonsub, Martin, Lane W.
• Format: Article
• Language: English
• Subjects: 140/133; 639/638/563/979; 639/766/25; 639/925/357/918; 639/925/357/918/1052; Ferroelectrics; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms7136

The next technological leap forward will be enabled by new materials and inventive means of manipulating them. Among the array of candidate materials, graphene has garnered much attention; however, due to the absence of a semiconducting gap, the realization of graphene-based devices often requires complex processing and design. Spatially controlled local potentials, for example, achieved through lithographically defined split-gate configurations, present a possible route to take advantage of this exciting two-dimensional material. Here we demonstrate carrier density modulation in graphene through coupling to an adjacent ferroelectric polarization to create spatially defined potential steps at 180°-domain walls rather than fabrication of local gate electrodes. Periodic arrays of p – i junctions are demonstrated in air (gate tunable to p – n junctions) and density functional theory reveals that the origin of the potential steps is a complex interplay between polarization, chemistry, and defect structures in the graphene/ferroelectric couple. The non-volatile modulation of charge carriers in graphene could be useful for future electronic devices. Here, the authors demonstrate that fields arising from ferroelectric polarization in periodically poled LiNbO 3 substrates can lead to a carrier modulation in adjacent graphene films.