HELPS CONTROL SIZE CHANGES IN NANOSCALE MATERIALS
Ark. – Newswise — Researchers want to build nanoscale
materials because they promise to be five to 10 times
stronger than conventional materials, which could lead
to longer-lasting computers and other electronic devices.
But these materials lose their attractive properties
at high temperatures. When it comes to making nanoscale
materials retain their size and shape at high temperatures,
a little “doping” appears to be in order, according
to University of Arkansas scientists.
Panneer Selvam, professor of civil engineering, graduate
students Paul Millett and Shubhra Bansal and Ashok Saxena,
dean of the College of Engineering reported their findings
at the Arkansas Academy of Sciences meeting. The paper
won first prize at the meeting for a poster presentation
and has been submitted to the Journal of the Arkansas
Academy of Science.
When building material atom by atom, temperature increases
change the size, shape and properties of the material—an
undesirable result for a stable component in a device.
Millett, Selvam, Bansal and Saxena created a computer
model using copper atoms, a material often used to create
connections between devices. The researchers introduced
an antimony atom to see how it would affect the properties
of the material.
The introduction of a different type of atom, called
“doping,” prevents the material from changing shape
and size and helps it retain its properties. Unlike
an alloy, where researchers might use mixtures of different
metal atoms to create more desirable properties, a “dopant”
atom remains separate from the other atoms in the metal,
migrating to its surfaces or edges.
In the simulation, the antimony atom moved through the
material to settle at the grain boundary, the place
where one layer of copper atoms ends and another layer
begins. Having an atom of a different size from the
main material changes the distance between the atoms,
which appears to allow the material to retain its shape
and size when the temperature changes. The researchers
ran the simulation with one antimony atom and 1800 copper
atoms, then ran it again with one antimony atom and
10,000 copper atoms.
“We can design new materials using processes like these,”
Selvam said. “This study tells manufacturers that they
can make these particular types of materials.”