Deutsche Welle, 27 Sep 2013
Scientists
in California say they have built a functioning microscopic computer made of
carbon "nanotubes" instead of silicon. The step could lead to faster,
ever-smaller electronic devices.
Stanford
University researchers said they have overcome downsizing limits posed by
silicon transistors in everyday computers by using tiny semiconductors from
rolled-up arrays of carbon atoms called "nanotubes" in a basic
computer.
Carbon
nanotubes are rolled-up, single-layer sheets of carbon atoms. Tens of thousands
can fit into the width of a single human hair.
The minute
prototype using several thousand carbon nanotubes (CNTs) was able to perform
basic counting and number-sorting functions, said engineering professor
Subhasish Mitra.
"People
have been talking about a new of carbon nanotube (CNT) electronics moving
beyond silicon," Mitra said. "Here is the proof."
Manufacture
possible
A Stanford University announcement - also covered by the journal Nature - quoted the
director of a computer chip design consortium, Naresh Shanbhag, as saying that
industrial-scale production of the CNT semiconductors was possible within
years.
Another
Stanford project leader, Philip Wong, said carbon nanotubes used less power and
were smaller than silicon circuits.
"CNT's
could take us at least an order of magnitude in performance beyond where you
can project silicon could take us."
He was
referring to a postulate first raised in 1965 that manufacturers can double the
density of silicon transistors roughly every two years, but only down to 5
nanometers. Silicon's limit is expected to be reached around 2020.
Furthermore,
silicon transistors packed onto conventional chips generate more heat and waste
power.
Stanford
University said its researchers had achieved an "unprecedented feat"
with the nanotube technology, which has been around for 15 years, by also
creating a "powerful algorithm" to handle imperfections in the carbon
tunnels and map out a circuit. This was "guaranteed to work no matter
whether or where CNTs might be askew," the university said.
'Significant
advance'
German
hybrid electronics expert, Frank Kreupl of the Munich's Technical University
commented in the Nature edition that the Stanford nanotube computer represented
a significant advance.
He added,
however, that the CNT transistors would have to become even smaller for the
technique to be feasible and the processors quicker.
ipj/hc (AFP, dpa)
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