Sandwiching
individual graphene sheets between insulating layers in order to
produce electrical devices with unique new properties, the method could
open up a new dimension of physics research.
Writing
in Nature Materials, the scientists show that a new side-view imaging
technique can be used to visualize the individual atomic layers of
graphene within the devices they have built. They found that the
structures were almost perfect even when more than 10 different layers
were used to build the stack.
This
surprising result indicates that the latest techniques of isolating
graphene could be a huge leap forward for engineering at the atomic
level.
This development gives more weight to graphene’s suitability as a major component in the next generation of computer chips.
The
researchers’ side-view imaging approach works by first extracting a
thin slice from the centre of the device. This is similar to cutting
through a rock to reveal the geological layers or slicing into a
chocolate gateaux to reveal the individual layers of icing.
The
scientists used a beam of ions to cut into the surface of the graphene
and dig a trench on either side of the section they wanted to isolate.
They then removed a thin slice of the device. Wonder material graphene
is a two dimensional material consisting of a single layer of carbon
atoms arranged in a honeycomb or chicken wire structure. It is the
thinnest material in the world and yet is also one of the strongest. It
conducts electricity as efficiently as copper and outperforms all other
materials as a conductor of heat.
Demonstrating
its remarkable properties won Professor Andre Geim and Professor Kostya
Novoselov the Nobel prize for Physics in 2010. The University of
Manchester is building a state-of-the-art National Graphene Institute to
continue to lead the way in graphene research.
Dr
Sarah Haigh, from The University of Manchester’s School of Materials,
said: “The difference is that our slices are only around 100 atoms thick
and this allows us to visualize the individual atomic layers of
graphene in projection.
“We
have found that the observed roughness of the graphene is correlated
with their conductivity. Of course we have to make all our electrical
measurements before cutting into the device. We were also able to
observe that the layers were perfectly clean and that any debris left
over from production segregated into isolated pockets and so did not
affect device performance.
“We plan to use this new side view imaging approach to improve the performance of our graphene devices.”
Source: University of Manchester
