In the recent issue of Nature, scientists from Empa and the Max Planck Institute for Polymer Research report how they have managed for the first time to grow graphene ribbons that are just a few nanometres wide using a simple surface-based chemical method. Graphene ribbons are considered to be hot candidates for future electronics applications as their properties can be adjusted through width and edge shape.
Transistors on the basis of graphene are considered to be potential successors for the silicon components currently in use. Graphene consists of two-dimensional carbon layers and possesses a number of outstanding properties: it is not only harder than diamond, extremely tear-resistant and impermeable to gases, but it is also an excellent electrical and thermal conductor. However, as graphene is a semi-metal it lacks, in contrast to silicon, an electronic band gap and therefore has no switching capability which is essential for electronics applications. Scientists from Empa, the Max Planck Institute for Polymer Research in Mainz (Germany), ETH Zrich and the Universities of Zrich und Bern have now developed a new method for creating graphene ribbons with band gaps.
Extremely narrow graphene ribbons
To date, graphene ribbons have been cut from larger graphene sheets, akin to tagliatelle being cut from pasta dough. Or carbon nanotubes were slit open lengthwise and unfurled. This gives rise to a band gap via a quantum mechanical effect the gap being an energy range that cannot be occupied by electrons and which determines the physical properties, such as the switching capability. The width (and edge shape) of the graphene ribbon determines the size of the band gap and thereby influences the properties of components constructed from the ribbon.
If extremely narrow graphene ribbons (well under 10 nanometres wide) that also have well-defined edges could be manufactured, so the reasoning, then they might allow f
|Contact: Dr. Roman Fasel|
Swiss Federal Laboratories for Materials Testing and Research (EMPA)