Probing voltage drop variations in graphene with photoelectron spectroscopy.

Voltage contrast X-ray photoelectron spectroscopy reveals graphene-substrate interaction in graphene devices fabricated on the C- and Si- faces of SiC

Charge neutrality and band-gap tuning of epitaxial graphene on SiC by molecular doping

Epitaxial graphene on SiC 0001 suffers from strong intrinsic n-type doping. We demonstrate that the excess negative charge can be fully compensated by noncovalently functionalizing graphene with the strong electronacceptor tetrafluorotetracyanoquinodimethane F4-TCNQ . Charge neutrality can be reached in monolayer graphene as shown in electron-dispersion spectra from angular-resolved photoemissi...

Monitoring the operation of a graphene transistor in an integrated circuit by XPS

One of the transistors in an integrated circuit fabricated with graphene as the current controlling element, is investigated during its operation, using a chemical tool, XPS. Shifts in the binding energy of C1s are used to map out electrical potential variations, and compute sheet resistance of the graphene layer, as well as the contact resistances between the metal electrodes. Measured shifts ...

Characterization of graphene oxide reduced through chemical and biological processes

The study of new materials for transparent electrodes or new heterojunctions made of 2D materials combinations is a very active research topic. Challenges to overcome are the modulation of the optoelectronic properties of such materials to achieve competitive photovoltaic devices. In this work, graphene oxide was reduced into graphene through different chemical (hydrazine, ultraviolet photocata...

Epitaxial graphene surface preparation for atomic layer deposition of Al2O3

Atomic layer deposition was employed to deposit relatively thick ( 30 nm) aluminum oxide (Al2O3) using trimethylaluminum and triply-distilled H2O precursors onto epitaxial graphene grown on the Si-face of silicon carbide. Ex situ surface conditioning by a simple wet chemistry treatment was used to render the otherwise chemically inert graphene surface more amenable to dielectric deposition. The...