The Graphene Dream

Our group's 2001 NSF proposal [Full Text]

The properties of nanoscopic graphitic ribbons are predicted to have much in common with carbon nanotubes. By tailoring their shapes (widths, passivating edge groups, edge roughness, crystallographic orientation) ribbon conductivity can be adjusted from semiconducting to metallic, just like nanotubes. Other properties that graphite ribbons share with nanotubes are (i) size-tunable electronic bandgaps, (ii) chemical robustness, (iii) immunity to electromigration (a major problem in nanoelectronics), (iv) high current capability, and (v) electrically tunable conductivity using the field effect via a proximal gate electrode ("gate-doping"). Just as for carbon nanotubes, carefullyprepared graphite ribbons are also predicted to be quasi-one-dimensional conductors, and possibly room temperature ballistic conductors, properties that would open new possibilities for nanoscale devices. However, in contrast to nanotubes, ribbons of different widths can be seamlessly joined, so that devices consisting of metallic and semiconducting sections can be patterned from a single graphite thin film, without foreign-metal contacts or junctions. This important property provides an easy path to large-scale integration, a goal that nanotube-based devices may never achieve. Our vision is nothing less than a new form of large-scale integrated electronics based on ultrathin films of lithographically-patterned graphite.

The first critical steps towards realizing this vision are embodied in a primary goal of this proposal: the development of an all-graphite field-effect transistor (grFET), which in its operation is closely related to the nanotube transistor. The grFET will not only show that robust nanoscale electronics can be realized, but will also blaze a clear path towards large-scale integration of these devices in contrast to nanotube devices.

This important goal will be achieved concurrently and interactively with investigations of fundamental properties of nanoscopic graphite objects. These investigations over a wide range of sizes include electronic and transport properties at ultra-low temperatures (0.007 K < T < 300K ) and at high magnetic fields (H ≤ 14 T), where quantum properties (i.e. quantum dot properties, coherent transport, quantum Hall effect) are most effectively probed.

These investigations will bear out whether room-temperature quantum confinement and ballistic transport can be achieved. This will result in a new class of ballistic transistors and devices based on the discrete electronic states in 2D graphitic quantum dots.

In order to achieve these goals the following research thrusts will be pursued:

  1. 1. Production of ultrathin epitaxial graphite films.
  2. 2. Production of graphitic nanostructures and devices.
  3. 3. Investigations of electronic properties of graphitic nanostructures and devices.
  4. 4. Investigations of transport properties of graphitic nanostructures and devices.

The team of Principle Investigators has been chosen carefully to provide complementary expertise and facilities for the project. Preliminary results of the team are encouraging.

Because it can be easily extended to large-scale integration (in contrast to nanotube electronics), the graphite field-effect transistor will rank among the most important achievements in nanoelectronics, possibly outweighing other alternatives such as molecular and nanotube electronics.

[Full Text]


"... all our science, measured against reality, is primitive and childlike –
and yet it is the most precious thing we have." - Einstein

Copyright © 2011 W.A. de Heer