Localized heating could be the key to mass-producing graphene nanocircuits
September 2, 2010
Scientists from the Georgia Institute of Technology have documented a major breakthrough in the production of nanocircuitry on graphene, a material that many envision as the successor of silicon for our electronics needs. Using thermochemical nanolithography (TCNL), the team found that the electrical properties of reduced graphene oxide (rGO) can be easily tuned to reliably produce nanoscale circuits in a single, quick step.
As the electronics industry keeps steadily pushing toward chip miniaturization, the physical limits of silicon transistors have been exposed and will soon constitute an insurmountable barrier that scientists need to address. The next proposed step is the replacement of silicon with a different material with better characteristics, and lately researchers seem to have put their eyes on graphene, a one-atom thick layer of carbon with a couple of aces up its sleeve: a better electrical conductance that makes for more energy-efficient computation, as well as its structure and dimensions, which open up the potential for much smaller, faster and even flexible electronics.
Despite the advantages that graphene could bring to the table, technological difficulties up until now have prevented us from reliably producing graphene nanostructures in a fast and inexpensive method, which is just what the Georgia Tech team has managed to achieve.
Rather than employing graphene in its purest form, the team used reduced graphene oxide (rGO). By using a heated atomic force microscope tip in a process called thermochemical nanolithography (TCNL), they simply heated the material at the nanoscale level and found out that, starting at 130 degrees Celsius (266F), it became up to 10,000 times more conductive than before.
Using the same method, they also produced nanowires with dimensions down to just 12 nanometers, effectively creating nanocircuits on graphene simply through finely localized heating, all without wearing of the microscope tip or of the sample material.
William P. King, associate professor in the Mechanical Science and Engineering department at the University of Illinois, expanded on the significant advantages of this technique. "First, the entire process happens in one step. You go from insulating graphene oxide to a functional electronic material by simply applying a nano-heater. Second, we think that any type of graphene will behave this way. Third, the writing is an extremely fast technique. These nanostructures can be synthesized at such a high rate that the approach could be very useful for engineers who want to make nanocircuits."
With ultra-fast graphene-based transistors achieving speeds of a whopping 300GHz recently being announced, it's clear how this breakthrough promises to have concrete repercussions in the scientific community in the months and years to come.
The team's research is detailed in the paper "Nanoscale Tunable Reduction of Graphene Oxide for Graphene Electronics" published in the journal Science.