Of Nanotechnology
and Tinkertoys
Song Jin | City College of the City University
of New York
When Song Jin was a child in Beijing, his family gave him the Chinese equivalent
of a chemistry set. He wired up a tomato and felt a tiny zap on his thumb.
Today he is at work on new ways to make the tiny stuff of nanotechnology
and perhaps help bring about the next era of computer chips.
His insights into nanomaterials — the things he once called his Tinkertoys — may
open the way to computers the size of a thread, ones that turn on instantly,
need little power and use the spin of electrons to compute.
Nanostructures such as nanowires and nanotubes are of both great scientific and technological interest.
“Higher speed, smaller, cheaper, less power, less heat,” he said. “These
things are all related. It’s mind boggling. But think of our progress.
Transistors for a tiny fraction of a cent.”
At the University of Wisconsin, Jin’s team is making whisker-like wires
billionths of a meter thick. Traditional computers are based on familiar aspects
of electrons — positive or negative charge, and the flow of electron
charges.
One new frontier for electronics is based on magnetic fields involved in
electron spin, thus the name spintronics. “It uses the ‘spin up’ and ‘spin
down’ to carry information,” Jin said.
His own work in spintronics began at Harvard as a post doc. Jin helped
achieve key breakthroughs in semiconducting, which got him thinking about
the future. “You
see a lot of interesting phenomena, increasing computing powers. It’s revolutionary,
in that no computers yet take advantage of spintronics — they do
not realize the full potential to process data. We hope to advance that
goal.”
The nature of materials is crucial. Spin-polarized current flows when thin
layers of metal film are aligned in devices using ferromagnets, like iron
or cobalt. Some of the components measure less than 100 billionths of a
meter. Jin’s
team will conduct tests to find the best formulas for nanomaterials.
“We want to advance technology,” he said, “and replace the
lack of exploitation.”
His team will transfer nanowires resembling hairs onto a surface where
he will deposit electrodes, using electronic lithography. They will heat
up the precursors, to a temperature at which they will decompose, then
watch as the compounds shift from vapor to solid, taking various shapes,
sometimes a thin cylinder. Then they will examine the tiny fibers, just
few microns across and maybe 10 times as long, with electron microscopes
to see how they’ve held up.
“We have a clever way of making them, and then looking to see their chemical
identities,” he said. “Then, eventually we will fabricate a
device, a prototypical component for a computer.”
But for him, the fun has only begun. “These things are interesting,” he
says. “Let’s take a look, investigate, make things, see what
new properties they have, and how we can use these properties to fabricate
useful devices.”
One result may be avoiding a slump some foresee for the evolution of computers. “Some
people predict the evolution will hit a brick wall of physical limits in 20 years. Nobody
knows. But humans are smart. Spintronics can bring things to the next level.
The consequences could revolutionize the whole game.”
At home, Jin listens to Mozart and Bach on an MP3 and reflects on the speed
of change. He’s glad to be in on the development of what soon may
become the nanoelectronics era.
