title: Bottom-gated epitaxial graphene.
abstract: High-quality epitaxial graphene on silicon carbide (SiC) is today available in wafer size. Similar to exfoliated graphene, its charge carriers are governed by the Dirac-Weyl Hamiltonian and it shows excellent mobilities. For many experiments with graphene, in particular for surface science, a bottom gate is desirable. Commonly, exfoliated graphene flakes are placed on an oxidized silicon wafer that readily provides a bottom gate. However, this cannot be applied to epitaxial graphene as the SiC provides the source material out of which graphene grows. Here, we present a reliable scheme for the fabrication of bottom-gated epitaxial graphene devices, which is based on nitrogen (N) implantation into a SiC wafer and subsequent graphene growth. We demonstrate working devices in a broad temperature range from 6 to 300  K. Two gating regimes can be addressed, which opens a wide engineering space for tailored devices by controlling the doping of the gate structure.
authors: Lehrstuhl für Angewandte Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen, Germany.
authors: Daniel
authors: D
authors: Waldmann
authors: Johannes
authors: J
authors: Jobst
authors: Florian
authors: F
authors: Speck
authors: Thomas
authors: T
authors: Seyller
authors: Michael
authors: M
authors: Krieger
authors: Heiko B
authors: HB
authors: Weber