Such is the importance of this new material that it could revolutionize the future of nanotechnology – it is expected that graphene will transform high-speed electronics and photonics, particularly as a replacement for silicon microchips and touchscreen technology, LCD displays and solar cells. Due to its strength and transparency, it is ideal for these applications, while its conductivity would offer a huge increase in efficiency on existing materials.
Up to now, it has only been possible to produce graphene – a relatively new form of carbon made up of a single layer of atoms arranged in a honeycomb-shaped lattice – in small flakes of tiny fractions of a millimeter. The study found that the most remarkable properties of graphene have been discovered in tiny flakes peeled off using Scotch tape. However, the new graphene sample was produced epitaxially on silicon carbide, showing that it can be made in a practical, scalable way.
The research, a collaboration between teams in the UK, Sweden and Italy, and published in Nature Nanotechnology (DOI: 10.1038/nnano.2009.474), made two significant breakthroughs: growing graphene to a sufficient size to be used in electronics, and being able to measure its electrical characteristics with unprecedented precision against an agreed international standard.
Team leader, Alexander Tzalenchuk, of the National Physical Laboratory in the UK, points out that “The measurements showed a unique ‘fingerprint’ of single layer graphene over a huge area (on the microelectronics scale of things). Large size and high quality of our graphene samples enabled very accurate resistance measurements, 10000 times more precise than the best previous result for graphene.”
It was crucial that a large area of epitaxial graphene demonstrated not only structural continuity, but also the degree of perfection required for precise electrical measurements on par with conventional semiconductors with a much longer development history.
There are a number of issues in broader technology that have to be solved before graphene can challenge the supremacy of semiconductors in electronics, such as reliable bandgap engineering in epitaxial graphene, control of carrier density and material engineering for graphene-based devices.
However, the research team now hope to demonstrate even more precise measurement, and at even higher temperatures, and are confident that certain graphene elements made by epitaxial growth will be ready for pre-production qualification around 2015.