Nanospectroscopy highlights

The exploitation of graphene in the next generation electronics depends on the capability of preserving and tailoring its electronic and transport properties. Substitutional implantation of exo-species into the C lattice mesh, B or N in particular, is an appealing functionalization method, as it is capable to alter the charge carrier density and even to open a bandgap. Since most devices require the fabrication of a heterojunction between a semiconducting active material and a metallic electrode, the development of lithographic tecniques for doping graphene is highly desirable. Here we report a proof-of-principle experiment demonstrating that low-energy N₂⁺ ion irradiation through an aperture mask can be used to achieve local control on the doping in graphene and to create a 2-dimensional heterojunction between n-doped and neutral single-layer graphene on Ir(111). LEEM, XPEEM-XPS and microprobe-ARPES

measurements, conducted at the Nanospectroscopy beamline at Elettra showed that the doping pattern is resistant to annealing in UHV up to 800 °C and that the doping level can be varied as function of the increasing irradiation dose without considerable damage for the C mesh. Our results pave the way to a miniaturization of graphene heterojunctions: doping lithography at the nanometer scale would allow the creation of 2D nanocircuits, with promising performances in terms of density, efficiency and thermal dissipation.

Retrieve article