Joshua Zide (right), assistant professor of materials science and engineering, at work in the laboratory with Pernell Dongmo, a doctoral candidate in the College of Engineering. Photo by Kathy F. Atkinson |
Joshua
Zide, assistant professor of materials science and engineering at the
University of Delaware, has spent nearly a decade engineering
nanomaterials using a technique called molecular beam epitaxy (MBE).
In
his research, Zide makes a class of materials called nanocomposites
that consist of metallic nanoparticles within a semiconductor. These
nanocomposites can be used in electronic devices such as transistors or
in energy conversion devices such as solar cells or thermoelectrics.
Typically, these devices are made of semiconductors like silicon or
gallium arsenide.
While
MBE produces nanoscale materials with exquisite control, the technique
is slow and expensive. It also doesn’t scale well for industrial
applications and it isn’t flexible in allowing the addition of new
materials.
Zide
will attempt to grow nanoscale materials in a new way through a 2012
Department of Energy Early Career Research grant from the Office of
Basic Energy Sciences. One of only 68 individuals selected from a pool
of nearly 850 applicants, the award will provide Zide $750,000 in
research funding over five years.
Under
the grant, Zide will explore the use of liquid phase epitaxy (LPE) to
make nanocomposites for thermoelectrics, which are devices for
generating electrical energy from heat. The work shows potential for
transitioning these promising materials from the laboratory to the
factory, allowing production of innovative electronic, optoelectronic
and energy conversion devices.
“People
have used LPE many times to make semiconductors. What we’re doing is
making the same kinds of nanocomposites using a hybrid approach that
also employs inert gas condensation,” he said.
The
research team will first make the metal nanoparticles in the laboratory
via inert gas condensation and then use the nanoparticles to grow
materials by LPE. According to Zide, combining these two
well-established, inexpensive techniques in a new way opens the door to
making this class of materials in a commercially viable and scalable
way.
“Instead
of growing nanomaterials at one micron per hour, which is much slower
than grass grows, LPE will enable us to grow nanomaterials at one micron
per minute,” Zide said.
“We
think this could lead to a faster, better, cheaper way of making a
class of nanocomposite materials with pretty exciting applications,” he
added.
Separating
the production of the nanoparticles from the production of the film
also increases the materials flexibility and enables it to be changed in
ways not possible by MBE. In principle, Zide said the technique could
also be applied to other materials systems, enabling researchers to
combine more dissimilar materials in electronic nanocomposites.
During
the project, he will collaborate and share equipment with materials
science and engineering colleagues Ismat Shah, whose expertise lies in
making nanoparticles via inert gas condensation, and Robert Opila, whose
expertise lies in LPE.
Two
graduate students will also participate in the project. One student
will focus on creating the nanoparticles and the other will incorporate
the nanoparticles into the films designed in Zide’s laboratory and to
study the materials’ characterization and properties.
“This long-term funding will enable me to lead my research in an entirely new direction,” Zide said.
Source: University of Delaware