nanotehnoloogia, nanoteknologia, nanotechnologija, nanotehnologijas, nanoteknologija,
nanotechnologii, nanotecnologia, nanotehnologijo, nanoteknik
PHILADELPHIA – Researchers at the University of Pennsylvania have announced that
they have bridged a major obstruction in the creation of nanoscale electronics
by developing a simple, reliable and observable method of creating tiny, tiny
gaps between electrodes.
Such "nanogaps" will make it possible to make electrical contact to structures
on the nanoscale –- billionths of a meter. In a recent edition of the journal
Applied Physics Letters, online now, physicists Marija Drndic and Michael Fischbein
describe the creation of nanogaps, which could have applications ranging from
ultra –fast electronics to quantum computing to high-speed gene reading.
"A number of people have proposed nanoelectronic devices that use nanogaps, but
nobody has been able to create nanogaps reliably in practice," said Marija Drndic,
an assistant professor in Penn's Department of Physics and Astronomy in the School
of Arts and Sciences. "For the first time, we were able to make the world's smallest
and cleanest nanometer gaps that can be imaged directly with atomic resolution.
These nanogaps can be used to electrically connect small objects, such as an
The ability to hook individual molecules -– whether they are the product of nanotechnology
or biotechnology -– to electronic circuits is the goal of many researchers. Such
systems will have applications in medicine, robotics, materials science and even
security. In addition, electronics on the nanoscale will be used to create denser,
faster storage devices and microprocessor chips.
To create these gaps, Drndic and graduate student Michael Fischbein used electron
beam lithography, a common nanotechnology tool that uses electrons to create
patterns on a surface. Their research succeeded where previous efforts failed
because of the type of surface they used, thin layers of silicon nitride.
"Electon beam lithography works on small scale, but it is limited down to about
10 nanometers." Drndic said. "It is not like drawing a line on a page; as an
electron beam hits a material the electrons tend to scatter forward and backward,
which makes it difficult to create tiny lines."
While other researchers focused on breaking small wires to create nanogaps, similar
to how a fuse can be popped open, the Penn researchers went the opposite route,
making the gaps directly.
"Contrary to many expectations, the thin layer of silicon nitride, which we used
instead of the usual ‘oxide on silicon,' helped minimize the amount of electron
scattering to the point where we could make clean gaps," Fischbein said.
Just as important, these nanogaps are compatible with high-resolution transmission
electron microscopy, or HRTEM. Because nanogaps are created on thin films, it
is easy to study the structure through HRTEM and assess their quality.
Already, the researchers have used nanogaps to measure electrical charge through
several coupled nanocrystals, which are also referred to as quantum dots. Previous
researchers have demonstrated that quantum dots can be manipulated to change
their physical properties, particularly their optical properties. In fact, the
blue laser, which will soon be put into use in commercial products, was a result
of early research in changing the colors of quantum dots.
"Nanogaps allow us to inject charge directly into individual nanocrystals, which
may enable us to control their properties on a quantum level," Fischbein said. "It
is a small gap, but across it we can bridge classical and quantum physics.”
This research was funded through grants from the National Science Foundation,
the Office of Naval Research and the American Chemical Society.
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