All carbon electronics based on graphene has been an elusive goal. For more than a decade, the inability to produce significant band-gaps in this material has prevented the development of semiconducting graphene. While chemical functionalization was thought to be a route to semiconducting graphene, disorder in the chemical adsorbates, leading to low mobilities, have proved to be a hurdle in its production. We demonstrate a new approach to produce semiconducting graphene that uses a small concentration of covalently bonded surface nitrogen, not as a means to functionalize graphene, but instead as a way to constrain and bend graphene. We demonstrate that a submonolayer concentration of nitrogen on SiC is sufficient to pin epitaxial graphene to the SiC interface as it grows, causing the graphene to buckle. The resulting 3-dimensional modulation of the graphene opens a band-gap greater than 0.7eV in the otherwise continuous metallic graphene sheet.
This paper is a report of a discovery that graphene grown on SiC which has previously been treated with NO will develop a bandgap. The paper includes hypotheses that explain the bandgap formation.
This research was supported by the NSF under Grants No.
1206655, and DMR-1206256, Additional support is also acknowledged from the NSF DMR-
1005880 and the W.M. Keck Foundation.
STM and STS experiments were
done at the Center for Nanoscale Materials supported by the U. S. Department of Energy,
Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Wang, F; Liu, G; Rothwell, S; Nevius, M; Tajeda, A; Taleb-Ibrahimi, A; Feldman, L C; Cohen, P I; Conrad, E H.
Widegap semiconducting graphene from nitrogen seeded SiC.
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