Fujitsu Laboratories has combined two of the great hopes for
far-generation electronics: carbon nanotubes and graphene.
Graphene, a single layer of carbon atoms whose structure resembles
chicken wire, is just about the fastest semiconductor available
and, unlike carbon nanotubes, it is compatible with planar wafer
processing.
However, graphene is difficult to grow, and good quality graphene
is impossible to grow. Instead it has to be flaked off blocks of
graphite by rubbing, and then stuck to a substrate.
Available synthesis techniques need around 700°C, whereas 400°C
would be more useful for electronics.
Now Fujitsu claims to have grown graphene on a substrate using a
forest of carbon nanotubes (CNTs), with the added benefit that CNTs
have incredible axial thermal conductivity.
"The composite structure is synthesised at a temperature of 510°C,
cooler than for conventional graphene formed at temperatures too
high for electronic device applications, thereby paving the way for
the feasible use of graphene as a material suitable for future
practical use in electronic devices which are vulnerable to
heat."
The laboratory said the CNTs are multi-walled, and that the
graphene varies from a few layers to a few dozen layers thick. So
far, the evidence is that the fastest electronic devices will come
from single or dual-layer graphene.
The material has not yet been evaluated in depth, but Fujitsu
expects the structure to have electrical conduction and thermal
dissipation in all directions.
"Fujitsu Laboratories will continue to explore the mechanisms by
which complex carbon nanostructures form and elucidate their
physical characteristics, in order to develop electronic device
application technologies that take advantage of those
characteristics," said Fujitsu. "In addition, in the field of
material sciences Fujitsu Laboratories will pursue the development
of technologies to enable the formation of high-quality carbon
nanostructures at a lower temperature."