We have seen this year IBM labs reporting on their method for giving graphene a band gap and then exceeding their own transistor speed record. This has been the way with graphene the last few years, one ground-breaking report after another.
So we’ve almost come to expect some news on the graphene front and last month we weren’t disappointed when a team of researchers reported in Science that they had developed a one-step process that uses a heated atomic force microscope (AFM) tip to tune the topographical and electrical properties of reduced graphene oxide for graphene-based electronics.
The researchers from Georgia Tech, the U.S. Naval Research Laboratory and the University of Illinois at Urbana-Champaign were partly inspired by the understanding that on the macroscale when graphene oxide is put into furnaces its properties can be changed from being an insulating material to a ore conductive graphene-like material. With this knowledge the researchers discovered that reduced graphene oxide started to become more conductive at 130 degrees Celsius.
In an article available on the Navy Research Laboratory’s website, Georgia Institute of Technology physicist Elisa Riedo notes, "We've shown that by locally heating insulating graphene oxide, both the flakes and epitaxial varieties, with an atomic force microscope tip, we can write nanowires with dimensions down to 12 nanometers. And we can tune their electronic properties to be up to four orders of magnitude more conductive. We've seen no sign of tip wear or sample tearing,"
According to William P. King, associate professor in the Mechanical Science and Engineering department at the University of Illinois at Urbana-Champaign, the research stands out for three reasons: 1) It can be accomplished in one step 2) They believe all graphene will behave this way (changing from an insulator to a conductor when heat is applied) 3) The writing process with the heated AFM tip can be accomplished at a high rate.
It seems graphene is continuing its astonishing run of breakthroughs. Maybe if it stays in the fields of electronics and photonics and away from tennis racquets and bicycles it can avoid the fate of carbon nanotubes and fall victim to the rants of NGOs, who like to cite inconclusive research as evidence for banning their use.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.