Graphene is a recently discovered carbon-based material only one (or a few) atom(s) thick.

In collaboration with our colleagues at NPL and beyond we deploy the arsenal of quantum metrology, functional scanning probe microscopy and nano-analysis to support the development and application of graphene electronic devices capable to sustain and extend performance scaling substantially beyond the fundamental limits of conventional technologies.

Graphene is hotly tipped to surpass conventional materials in many important applications, such as super-capacitors, ultrafast analogue transistors and touch-screen displays.

Metrology is called upon to underpin these developments. Today graphene has already found an application in electrical metrology, where NPL and collaborators have demonstrated a graphene-based quantum Hall resistance standard superior to those based on silicon field-effect transistors and group III-V semiconductors presently used. The quantum Hall effect is a benchmark test of the material quality. Demonstration of the accurate and robust quantum Hall effect showed that graphene devices belong to the same elite club as silicon field-effect transistors and group III-V semiconductor heterostructures with a much longer development history.

Major results [see 6 for 2011 review]

• Single layer graphene over huge area (on the microelectronics scale of things) with a fairly uniform carrier density [1].
• Theory of charge transfer between graphene and the substrate [2].
• Electrostatic force microscopy identifying domains in epitaxial graphene with different number of atomic layers [5].
• Polymer encapsulation improving graphene mobility and stability [3, read more]
• Non-volatile, non-invasive, and reversible photochemical gating of epitaxial graphene improving the robustness of QHE [3, read more].
• Exact (to within 8.6x10-11) and extremely robust quantisation in graphene - a material very different from a classical semiconductor [4, 7].
• A new embodiment of the QHE resistance standard - based on epitaxial graphene [1, 7, read more].
• Wettability of one and few layers of graphene on nanoscale [8].

Collaboration:

We collaborate with many world-leading research groups, but in particular:

• Prof Sergey Kubatkin (Chalmers University, Sweden) - fabrication and properties
• Prof Rositza Yakimova (Linköping University, Sweden) - growth
• Prof Vladimir Fal'ko (Lancaster University, UK) - theory
• Dr Vladimir Antonov (Royal Holloway, University of London, UK) - photon detectors

Recent Publications

1. A. Tzalenchuk, S. Lara-Avila, A. Kalaboukhov, S. Paolillo, M. Syväjärvi, R. Yakimova, O. Kazakova, T. J. B. M. Janssen, V. Fal'ko and S. Kubatkin
   Towards a quantum resistance standard based on epitaxial graphene
   Nature Nanotechnology 5, 186-189 (2010).
2. S. Kopylov, A. Tzalenchuk, S. Kubatkin and V. Fal’ko
   Charge transfer between epitaxial graphene and silicon carbide
   Applied Physics Letters 97, 112109 (2010).
3. S. Lara-Avila, K. Moth-Poulsen, R. Yakimova, T. Bjørnholm, V. Fal'ko, A. Tzalenchuk, and S. Kubatkin
   Nonvolatile Photo-Chemical Gating of an Epitaxial Graphene - Polymer Heterostructure
   Advanced Materials, 23, 878-882 (2011).
4. T. J. B. M. Janssen, A. Tzalenchuk, R. Yakimova, S. Kubatkin, S. Lara-Avila, S. Kopylov, and V. I. Fal'ko
   Anomalously strong pinning of the filling factor ν = 2 in epitaxial graphene
   Physical Review B 83, 233402 (2011)
5. T. Burnett, R. Yakimova, and O. Kazakova
   Mapping of local electrical properties in epitaxial graphene using Electrostatic Force Microscopy
   Nano Letters, 11, 2324-2328 (2011)
6. A. Tzalenchuk, S. Lara-Avila, K. Cedergren, M. Syväjärvi, R. Yakimova, O. Kazakova, T. J. B. M. Janssen, K. Moth-Poulsen, T. Bjørnholm, S. Kopylov, V. Fal'ko, and S. Kubatkin
   Engineering and metrology of epitaxial graphene
   Solid State Communications, 151, 1094-1099 (2011)
7. T.J.B.M. Janssen, N.E. Fletcher, R. Goebel, J.M. Williams, A. Tzalenchuk, R. Yakimova, S. Kubatkin, S. Lara-Avila, and V.I. Fal'ko
   Graphene, universality of the quantum Hall effect and re-definition of the SI
8. T. L. Burnett, J. Patten and O. Kazakova
   Water desorption and re-adsorption on epitaxial graphene studied by SPM
9. Small Epitaxial Graphene Devices for Magnetosensing Applications
   V. Panchal, K. Cedergren, R. Yakimova, A. Tzalenchuk, S. Kubatkin, and O. Kazakova
   J. Appl. Phys., 111, 07E509 (2012)
10. Identification of epitaxial graphene domains and adsorbed species in ambient conditions using quantified topography measurements
    T. L. Burnett, R. Yakimova, and O. Kazakova
    J. Appl. Phys., 112, 054308 (2012)
11. Surface potential variations in epitaxial graphene devices investigated by Electrostatic Force Spectroscopy
    V. Panchal, T. L.  Burnett, R. Pearce, K. Cedergren, R. Yakimova, A. Tzalenchuk, and O. Kazakova
    12th IEEE Conference on Nanotechnology (IEEE-NANO), 1-5 (2012)
12. Ferromagnetism in nanomesh graphene
    G. Ning, C. Xu, L. Hao, O. Kazakova, Z. Fan, H. Wang, K. Wang, J. Gao, W. Qian, and F. Wei
    Carbon, 51, 390 (2013)

Epitaxial Graphene Sensors for Detection of Small Magnetic Moments
V. Panchal , D. Cox , R. Yakimova , and O. Kazakova
IEEE Trans. Mag., 49, 97 (2013)

Major projects

Graphene research is presently funded by:

• The NPL Strategic Research programme
• Pathfinder programme of the National Measurement Office
• FP7 project ConceptGraphene