Controllable N-Doping of Graphene

Abstract

Opening and tuning an energy gap in graphene are central to many electronic applications of graphene. Here we report N-doped graphene obtained by NH3 annealing after N(+)-ion irradiation of graphene samples. First, the evolution of the graphene microstructure was investigated following N(+)-ion irradiation at different fluences using Raman spectroscopy, showing that defects were introduced in plane after irradiation and then restored after annealing in N2 or in NH3. Auger electron spectroscopy (AES) of the graphene annealed in NH3 after irradiation showed N signal, however, no N signal was observed after annealing in N2. Last, the field-effect transistor (FET) was fabricated using N-doped graphene and monitored by the source-drain conductance and back-gate voltage (Gsd-Vg) curves in the measurement. The transport property changed compared to that of the FET made by intrinsic graphene, that is, the Dirac point position moved from positive Vg to negative Vg, indicating the transition of graphene from p-type to n-type after annealing in NH3. Our approach, which provides a physical mechanism for the introduction of defect and subsequent hetero dopant atoms into the graphene material in a controllable fashion, will be promising for producing graphene-based devices for multiple applications.

Selective Ionic Transport through Tunable Subnanometer Pores in Single-Layer Graphene Membranes

“…While we have used ion bombardment as a highly controllable method to induce defects, 26,41 growth of defects formed during graphene synthesis through doping 42 or other methods 9,23 will further enhance the scalability of this approach. These results represent a significant advancement in the development and the future realization of nanoporous graphene-based membranes.…”

Surface modification of graphene and graphite by nitrogen plasma: Determination of chemical state alterations and assignments by quantitative X-ray photoelectron spectroscopy

“…Multi-layer graphene powder (MLGR), (consisting of about 6 atomic layers), obtained by mechanical exfoliation of high purity synthetic graphite (Aldrich, USA) [15], was disaggregated in carbon tetrachloride by ultrasonication. Thin films were prepared from this slurry by drop-wise deposition and drying onto a stainless steel holder (Ø 9 mm) that was designed for the plasma treatment and the "in-situ" XPS measurements.…”

“…The method is solvent-free, thereby minimizing reaggregation of the graphene flakes. The temperature and the duration of the treatment allow for further fine tuning of the nitrogen content [15,16]. Recent reviews on the synthesis of nitrogen doped graphene or graphene oxide [17,18] also underscore that the efficiency of plasma treatment in nitrogen doping considerably exceeds other methods.…”

Mobility Improvement and Microwave Characterization of a Graphene Field Effect Transistor With Silicon Nitride Gate Dielectrics

“…Also it should be noted that before silicon nitride deposition, the Dirac point was at a positive voltage (V Dirac =35-50V) and carrier mobilities in the range of µ e =2500-3000 cm 2 /Vs, µ h =3500-4000 cm 2 /Vs. One possible reason for shifting of the Dirac point can be the reaction of the nitrogen atoms (NH 3 ) presented in the PECVD process with graphene [17] and also it is shown that in the presence of the NH 3 absorbent, graphene conductivity becomes higher when the channel is carried by electrons rather than holes [18]. …”