New technique enables nanoscale patterns to be cut in graphene without compromising its electrical properties
Graphene moves a step closer to commercialisation with new method encapsulating graphene inside another two-dimensional material
Graphene researchers claim to have devised a novel technique to carve out the material to nanoscale dimensions without destroying its electrical properties.
According to the researchers, the new method enables 100 to 1000 times more electrical current to flow in the material than earlier reported for lithographically carved nanographene.
Graphene has been described as a 'wonder material' thanks to some its unusual properties. It is ultra-lightweght, extremely strong and flexible, highly elastic, and also an exceptional conductor of electricity.
Since its discovery in 1962, researchers have attempted to exploit graphene to create nano-sized electronics, but have found very little success in their endeavours.
Theoretically, quantum properties of graphene can be easily altered by creating a very fine pattern of holes in it and inducing a band gap. These little changes ought to make it perfect for use in various applications including electronics and photonics.
But this simple task turns out to be highly challenging when researchers actually attempt to create tiny pattern in graphene layer. Since graphene is just one atom thick, all atoms are exposed to the outside world, and even a tiny irregularity in the pattern destroys its electrical properties.
Now, Graphene Flagship researchers at Technical University of Denmark (DTU) claim to have found a new technique to solve the problem. Lene Gammelgaard and Bjarke Jessen, two postdocs from DTU Physics, encapsulated graphene inside hexagonal boron nitride (a two-dimensional insulating material) and then carefully created a dense array of nanoscopic holes in the layer using electron beam lithography.
According to the researchers, the holes are about 10 nanometres in radius and located at a distance of 12 nanometres from other holes. The roughness at the edge of the holes is less than one nanometre. This precision allows 100 to 1000 times more electrical than earlier reported for lithographically carved nanographene.
"We have shown that we can control graphene's band structure and that deterministic design of nanoelectronics is realistic.
"Looking solely at electronics, this means that we can make insulators, transistors, conductors and perhaps even superconductors, as our nanolithography can preserve the subtle inter-layer physics that was recently shown to lead to superconductivity in double-layer graphene." said Peter Bøggild, researcher at DTU and a co-author of the study paper.
"There are plenty of practical challenges, but the fact that we can tailor electronic properties of graphene is a big step towards creating new electronics with extremely small dimensions," he added.
The findings of the study are published in journal Nature Nanotechnology.