nanotehnoloogia, nanoteknologia, nanotechnologija, nanotehnologijas, nanoteknologija,
nanotechnologii, nanotecnologia, nanotehnologijo, nanoteknik
A slice of carbon
could work wonders with chips
Friday 21 April 2006
Move over silicon: the hottest new material in electronics
could be sitting inside the humble pencil. At the
Institute of Physics' Condensed Matter and Materials
Physics conference at the University of Exeter on
Thursday 20 and Friday 21 April, Andre Geim of the
University of Manchester and his colleagues claim
that graphite, the silvery black, soft form of carbon
known for thousands of years, could yield a new generation
of microelectronic devices, as well as unveiling
unprecedented effects in quantum physics.
But this is no ordinary graphite. The stuff in ordinary pencils consists of
stacked sheets of carbon, each sheet made up of atoms linked together to form
a hexagonal network like chicken wire. Geim and colleagues have discovered
that interesting and potentially useful electronic behaviour appears when these
sheets are separated and laid out one sheet at a time.
A single graphite sheet is called graphene. This same gossamer-thin material
has attracted intense interest over the past ten years or so when it is rolled
up into long, hollow cylinders called carbon nanotubes. Nanotubes are predicted
to be extremely strong, and they conduct electricity in ways that have already
been exploited to make electronic devices smaller than any made by conventional
silicon-chip fabrication methods.
But Geim and colleagues say that the appeal of this kind of carbon lies not
with nanotubes in themselves, but with the underlying fabric: the flat sheets
of graphene. They have developed methods for splitting graphite apart into
its separate layers and lying them down flat on a surface, where their electrical
properties can be studied. A graphene sheet is electrically conducting, behaving
essentially like a two-dimensional metal. But it is a strange kind of metal,
with properties dictated by quantum mechanics. For example, even if there are
no mobile electrons to carry an electrical current, the electrical conductivity
can never fall below a certain minimum value: it is like an electron gate that
can never be fully closed.
And the Manchester researchers have shown that graphene can be fashioned into
a device called a spin valve, which discriminates between mobile electrons
according to their spin. Spin is a quantum-mechanical property of electrons,
and can take either of two values - somewhat akin to magnets that can orient
their poles in either of two opposed directions. Conventional electronics takes
no account of electron spin; but it has been suggested that a spin-dependent
form of electronics, called spintronics, could provide new and powerful ways
to process information. A graphene spin valve could act rather like a spintronic
filter that lets a current pass only if the electrons have the correct spin.
The presentation 'Graphene-Based Single Electron Transistor' will be delivered
at 12:30 on Friday 21 April 2006 at the Institute of Physics conference Condensed
Matter and Material Physics.
See press release PR11(06) press
story has been adapted from a news release -
Diese Meldung basiert auf einer Pressemitteilung
tekst is gebaseerd op een nieuwsbericht -
the wave ?
some news ?
click on archive photo
how about joining us
contacting us ?