takes nanotechnology to new frontiers (NASA)
- Working with materials that are not visible to the naked
- NRI scientist and his three colleagues had convinced the
US Congress to launch the National Nanotechnology Initiative
when the technology was not even heard of.
- Some $1 billion earmarked every year, with Meyyappan
and his team of 60 scientists working on making nanotechnology
available for future space exploration
- One nano is 10,000 times finer than the thickness of a
human hair. A technology using such ultra fine material
is thus an invaluable resource for innumerable applications
- Nanotechnology could be used for electronic devices, sensors,
super-strong lightweight material and a variety of other
- "Nanotechnology space application is just one of
the many areas," Meyyappan says. "The larger benefits
will be in health, medicine, transportation, computers -
almost every sector of daily life." For example, it
could be used for a more effective drug delivery or early
warning diagnostics. It could also be a cheaper source of
energy, he reels off.
- he US space agency NASA is looking at nanotechnology for
its future needs on electronics, computing, sensors, and
advanced miniaturization of all systems.
Dr. Meyya Meyyappan born in Karaikudi
in southern India's Tamil Nadu state, Meyyappan said he did
not even dream as a student he would eventually end up in
NASA, but he did know he wanted to be an engineer.
In 1979, he came to the US to study chemical engineering
at the Clarkson University in New York. He went on to do his
Ph.D. on micro-gravity materials processing, with the research
funded by NASA. "Even though I did my Ph.D. in a field
related to NASA, I did not get a job with the organisation
because I was not a US citizen,"
He joined Scientific Research Associates, a private company
based in Glastonbury, Connecticut. For 12 years he worked
on microelectronic devices and device processing "and
a lot of things that had nothing to do with NASA".
Eight years ago, NASA came knocking at his door and recruited
him to start a nanotechnology programme because he was working
on quantum devices, a precursor to the technology. Now he
is a director of center for Nanotechnology at NASA, Ame.
Meanwhile, Meyyappan and a few colleagues began discussing
the need for developing a national effort on nanotechnology.
In 1997, Four of us approached the Clinton administration
and Congress to push our programme through. Both Clinton and
Congress were impressed and that's why we have the Nanotechnology
Initiative which was approved in 1999 and started in 2000.
The Center for Nanotechnology in California has about 60 scientists
working on various aspects of nanotechnology including carbon
nanotubes for nanoelectronics, sensors and detectors, molecular
Inorganic nanowires are being tested for sensors and devices,
while protein nanotubes, nanotechnology in gene sequencing,
nano-bio fusion, quantum computing, computational nanotechnology,
computational quantum electronics and opto-electronics are
the other areas that scientists are working on.
Dr. Meyya Meyyappan is the Director and Senior Scientist
at Ames Center for Nanotechnology in Moffett Field,
CA. His team is presently researching and developing carbon
NASA Tech Briefs: How long has the NASA Ames Center for Nanotechnology
been operating and what are your principal duties as Director?
Dr. Meyyappan: We started as a small group in 1996, and since
then, the center has grown to have 50 full-time scientists.
In addition to these scientists, we also have visiting faculty,
graduate and undergraduate students, and high school students
working with us on various projects. Our nano center is the
largest in-house nanotechnology effort within the government,
and it is also one of the largest in the world.
As the director, I am basically in charge of all the technical
aspects; I provide vision and what kind of projects we will
work on. I am also the senior scientist, which means that
I also do technical work.
NTB: What nanotechnology projects are you currently working
Dr. Meyyappan: We have a few areas as our primary focus.
First, we are using nanotechnology in the area of electronics
and computing, or nanoelectronics and computing. We are also
developing nanotechnology-based sensors and detectors, and
we are utilizing nanotechnology in gene sequencing. Our project
focus is primarily material-driven and we are looking at a
variety of nanoscale materials. The first and the major focus
is on carbon nanotubes.
The next class of materials that we are working with is inorganic
nanowires, like zinc oxide and gallium nitride, for the manufacture
of sensors and detectors. The third class of materials is
protein-based nanotubes, which are biological. We synthesize
them in large quantities and purify them. We are using them
for applications like templates for lithography.
We are using the fourth class of materials, organic molecules,
as a conducting channel to make electronic devices. We synthesize
these organic molecules and we try to make a logic chip or
a memory chip.
In nanotechnology research, it is not just enough to do experimental
work. In order to make sense of the results and to understand
the work that we are doing, it is very important to have complimentary
supporting modeling work. We therefore have a group of people
who do modeling and simulation.
NTB: What are carbon nanotubes?
Dr. Meyyappan: Carbon nanotubes look like nanoscale cylinders,
about 1 nm or so in diameter and a few microns long. Imagine
rolling up a sheet of graphite into a tube; that is what we
are talking about. There are a few procedures in the lab we
are using to grow these structures. One method is called Chemical
Vapor Deposition (CVD), which uses some hydrocarbon gases
such as methane with a catalyst material like iron. In the
second method, called plasma enhanced CVD, we use low temperature
plasmas to grow nanotubes.
NTB: What is it about the structure of nanotubes that makes
them so versatile and functional to all of these diverse industries?
Dr. Meyyappan: Carbon nanotubes are very unique in the sense
that they have extraordinary mechanical properties. For example,
compared to steel, nanotubes have a strength-to-weight ratio
of 500. At the same time, nanotubes can be used to make a
computer chip, because in addition to these wonderful mechanical
properties they also have very exciting electrical properties.
A nanotube, depending on its growth conditions and its diameter,
can be a metal or a semiconductor, allowing us to create semiconductor-metal
and semiconductor-semiconductor junctions.
What is unique about this material is that historically,
all the materials we used for computer chip applications were
impractical for construction of an aircraft. The same with
aluminum or stainless steel; these metals could be used to
manufacture an automobile, but they could never be used to
make a computer chip. This unique material, which is still
emerging, can be used for both fine applications like computer
chips and sensors, and for massive applications in the aerospace
and automotive industries. The reason why people are so excited
about this technology is that it is versatile and covers a
whole range of applications.
NTB: Has NASA used carbon nanotubes recently?
Dr. Meyyappan: We are pretty much in the research stage.
NASA has a measuring system called the Technology-Readiness
Level that measures how close a technology is to deployment.
The scale goes from 1 to 9. The technology at the level 1
or 2 is at basic research. At level 4 or 5, the gap between
research and final deployment is bridged. Our technology readiness
level with nanotubes is primarily level 1 or 2, but I believe
that in a few years time we will slowly start migrating
up the ladder towards deploying the actual application.
NTB: Do you have a specific time frame in mind?
Dr. Meyyappan: There are actually some applications that
are already beginning to emerge. First, we have used carbon
nanotubes as a tip in an atomic force microscope, a technology
that allows you to look at things at the atomic level. It
provides the so-called eye to see something at
atomic scale. Carbon nanotubes provide the resolution to look
at something on that level, and are also able to survive for
a long time -- even week after week.
Not only does it have tremendous applications for NASA, but
it also has immediate applications in the semiconductor industry.
In silicon manufacturing today, we have to profile trenches,
which are very narrow holes, probably about a few microns
deep. People want to know what the profile looks like, which
means that we have to use something sharp in there to trace
the profile. This is called a profilometer, and we were able
to demonstrate that carbon nanotube tips could be used as
a profilometer. That technology is actually being very warmly
embraced by the semiconductor industry. NASA Ames spun off
a company about six months ago that is attempting to mass
produce and market these carbon nanotube tips for the semiconductor
We are also trying to create biosensors using carbon nanotubes
because biosensors are important to NASA in terms of astrobiology
applications. Currently, we are also involved in a big program
with the National Cancer Institute to develop carbon nanotube-based
biosensors for cancer diagnostics. I believe broader applications
will occur in about two to five years, but the majority of
them will have applications only after a decade.
- NASA has needs in miniaturization of sensors, instrumentation
and all aspects of payload for future missions. Realization
of microspacecraft and autonomous spacecraft would require
advances in nanoelectronics. All of these goals are expected
to benefit from nanotechnology. This talk will provide an
overview of nanotechnology program goals within NASA and
how nanotechnology is expected to benefit various missions.
This talk will also discuss in detail carbon nanotube research
at NASA Ames.
- Carbon nanotube (CNT) was discovered in the early 1990s
and is an off-spring of C60 (the fullerene or buckyball).
CNT, depending on chirality and diameter, can be metallic
or semiconductor and thus allows formation of metal-semiconductor
and semiconductor junctions. CNT exhibits extraordinary
mechanical properties: Young's modulus over I Tera Pascal,
tensile strength of 200 GPa and a high breaking strain.
Its thermal conductivity in the axial direction is comparable
to thin film diamond. The combination of remarkable mechanical
properties and unique electronic properties offers significant
potential for revolutionary applications in electronics
devices, computing and data storage technology, sensors,
composites, storage of hydrogen or lithium for battery development,
nanoelectromechanical systems (NEMS), and as tip in scanning
probe microscopy (SPM) for imaging and nanolithography,
Thus the CNT synthesis, characterization and applications
touch upon all disciplines of science and engineering. This
talk will provide an overview of experimental and computational
research in progress at NASA Ames and discuss challenges
and opportunities ahead.