NANOTECHNOLGY
MEMBERS-KHUSHBU KATARIA, NIKET KARIA.
V.E.S.P. CHEMBUR, MUMBAI.
ABSTRACT:-Nanotechnology refers broadly to a field of applied science and
technology whose unifying theme is the control of matter on a scale smaller than
1 micrometer, normally 1 to 100 nanometers, and the fabrication of devices
within that size range.
It is a highly multidisciplinary field, drawing from fields such as applied physics,
materials science, colloidal science, device physics, supramolecular chemistry,
and even mechanical and electrical engineering. Nanotechnology can be seen as
an extension of existing sciences into the nanoscale, or as a recasting of existing
sciences using a newer, more modern term.
KEYWORDS:- Nanotechnology, Nanosystems, Nanocrystals, Nanotubes,
Nano.
INTRODUCTION
The term "nanotechnology" was defined by Tokyo Science University Professor
Norio Taniguchi in a 1974 paper ”Nano-technology” mainly consists of the
processing of separation, consolidation, and deformation of materials by one
atom or by one molecule." In the 1980s the basic idea of this definition was
explored in much more depth by Dr. K. Eric Drexler, who promoted the
technological significance of nano-scale phenomena and devices through
speeches and the books Engines of Creation.
The Coming Era of Nanotechnology (1986) and Nanosystems: Molecular
Machinery, Manufacturing, and Computation, and so the term acquired its current
sense.
Nanotechnology and nanoscience got started in the early 1980s with two major
developments; the birth of cluster science and the invention of the scanning
tunneling microscope (STM). This development led to the discovery of fullerenes
in 1986 and carbon nanotubes a few years later.
In another development, the synthesis and properties of semiconductor
nanocrystals was studied. This led to a fast increasing number of metal oxide
nanoparticles of quantum dots. The atomic force microscope was invented.
NANOTECHNOLOGY
The term nanotechnology itself has been variously defined. By one defination, it
is the ability to do many things; measure, see, predict and make – on the scale of
atoms and molecules. Nanotechnology has also
Bees defined to be dealing with materials in the range of 0.1 to 100 nanometers.
It is also referred as the term for the construction and utilization of functional
structures with at least one characteristic dimension measured in nanometers.
Nanoscience and nanotechnology only became possible in the 1910s with the
development of the first tools to measure and make nanostructures. But the
actual development started with the discovery of electrons and neutrons which
showed scientists that matter can really exist on a much smaller scale than what
we normally think of as small, and/or what they thought was possible at the time.
It was at this time when curiosity for nanostructures had originated.
CHALLENGES CONFRONTING NANOTECHNOLOGY
The Tiniest Wires
An image from a scanning tunneling microscope (STM) reveals metallic wires
only eight to ten atoms wide. Researchers at Hewlett-Packard Company in Palo
Alto, California, developed the nanowires, the tiniest wires yet created.
Nanowires could lead to a variety of applications, including extremely small and
fast computers.
Paul Sakuma/AP/Wide World Photos
A major challenge facing nanotechnology is how to make a desired
nanostructure and then integrate it into a fully functional system visible to the
human eye. This requires creating an interface between structures built at the
nanometres scale and structures built at the micrometer scale. A common
strategy is to use the so-called “top-down meets bottom-up” approach. This
approach involves making a nanostructure with tools that operate at the
nanoscale, organizing the nanostructures with certain assembly techniques, and
then interfacing with the world at the micrometer scale by using a top-down
nanofabrication process.
However, technical barriers exist on the road toward this holy grail of
nanotechnology. For example, the bottom-up approach generally yields
nanocrystals of 1 nm, a dimension that is too small for current nanofabrication
techniques to interact with. As a result, interfacing a nanocrystal with the outside
world is a highly complex and expensive process. A novel procedure must be
developed to overcome this barrier before many of the synthetic nanostructures
can become part of mainstream industrial applications. Also, as the size of the
nanostructure gets increasingly thinner, the surface area of the material
increases dramatically in relation to the total volume of the structure. This
benefits applications that require a big surface area, but for other applications
this is less desirable. For example, it is undesirable to have a relatively large
surface area when carbon nanotubes are used as an electrical device, such as a
transistor. This large surface area tends to increase the possibility that other
unwanted layers of molecules will adhere to the surface, harming the electrical
performance of the nanotube devices. Scientists are tackling this issue to
improve the reliability of many nanostructure-based electronic devices.
Another important issue relates to the fact that the properties of nanocrystals are
extremely sensitive to their size, composition, and surface properties. Any tiny
change can result in dramatically different physical properties. Preventing such
changes requires high precision in the development of nanostructure synthesis
and fabrication. Only after this is achieved can the reproducibility of
nanostructure-based devices be improved to a satisfactory level. For example,
although carbon nanotubes can be fashioned into high-performance transistors,
there is a significant technical hurdle regarding their composition and structure.
Carbon nanotubes come in two “flavors”; one is metallic and the other is
semiconducting. The semiconducting flavor makes good transistors. However,
when these carbon nanotubes are produced, mixtures of metallic and
semiconducting tubes are entangled together and so do not make good
transistors. There are two possible solutions for this problem. One is to develop a
precise synthetic methodology that generates only semiconductor nanotubes.
The other is to develop ways to separate the two types of nanotubes. Both
strategies are being researched in labs worldwide.
NANOTECHNOLOGY RESEARCH
Major centers of nanoscience and nanotechnology research are found at
universities and national laboratories throughout the world. Many specialize in
particular aspects of the field. Centers in nanoelectronics and photonics (the
study of the properties of light) are found at the Albany Institute of
Nanotechnology in Albany, New York; Cornell University in Ithaca, New York; the
University of California at Los Angeles (UCLA); and Columbia University in New
York City. In addition, Cornell hosts the Nanobiotechnology Center.
Universities with departments specializing in nanopatterning and assembly
include Northwestern University in Evanston, Illinois, and the Massachusetts
Institute of Technology (MIT) in Cambridge. Biological and environmental-based
studies of nanoscience exist at the University of Pennsylvania in Philadelphia,
Rice University in Houston, and the University of Michigan in Ann Arbor. Studies
in nanomaterials are taking place at the University of California at Berkeley and
the University of Illinois in Urbana-Champaign. Other university-affiliated
departments engaged in nanotechnology research include the Nanotechnology
Center at Purdue University in West Lafayette, Indiana; the University of South
Carolina NanoCenter in Columbia; the Nanomanufacturing Research Institute at
Northeastern University in Boston, Massachusetts; and the Center for Nano
Science and Technology at Notre Dame University in South Bend, Indiana. By
2003 more than 100 U.S. universities had departments or research institutes
specializing in nanotechnology.
Other major research efforts are taking place at national laboratories, such as the
Center for Integrated Nanotechnologies at Sandia National Laboratories in
Albuquerque and at Los Alamos National Laboratory, both in New Mexico; the
Center for Nanophase Materials Sciences at Oak Ridge National Laboratory in
Tennessee; the Center for Functional Nanomaterials at Brookhaven National
Laboratory in Upton, New York; the Center for Nanoscale Materials at Argonne
National Laboratory outside Chicago, Illinois; and the Molecular Foundry at the
Lawrence Berkeley National Laboratory in Berkeley, California.
Internationally, the Max-Planck Institutes in Germany, the Centre National de la
Recherche Scientifique (CNRS) in France, and the National Institute of Advanced
Industrial Science and Technology of Japan are all engaged in nanotechnology
research.
FUTURE IMPACT OF NANOTECHOLOGY
NANOTUBEWIRE
A blue carbon nanotube wire just 10 atoms wide lies against platinum electrodes
in an image magnified 120,000 times. The wire, which is .0000015 mm
(.0000001 in) in diameter, is an example of the type of circuitry that might
someday be used in next-generation computer technology, such as molecular
computers.
S.J. Tans et al, Delft University of Technology/Science Photo Library/Photo
Researchers, Inc.
Nanotechnology is expected to have a variety of economic, social,
environmental, and national security impacts. In 2000 the National Science
Foundation began working with the National Nanotechnology Initiative (NNI) to
address nanotechnology’s possible impacts and to propose ways of minimizing
any undesirable consequences.
For example, nanotechnology breakthroughs may result in the loss of some jobs.
Just as the development of the automobile destroyed the markets for the many
products associated with horse-based transportation and led to the loss of many
jobs, transformative products based on nanotechnology will inevitably lead to a
similar result in some contemporary industries. Examples of at-risk occupations
are jobs manufacturing conventional televisions. Nanotechnology-based fieldemission or liquid-crystal display (LCD), flat-panel TVs will likely make those jobs
obsolete. These new types of televisions also promise to radically improve
picture quality. In field-emission TVs, for example, each pixel (picture element) is
composed of a sharp tip that emits electrons at very high currents across a small
potential gap into a phosphor for red, green, or blue. The pixels are brighter, and
unlike LCDs that lose clarity in sunlight, field-emission TVs retain clarity in bright
sunlight. Field-emission TVs use much less energy than conventional TVs. They
can be made very thin—less than a millimeter—although actual commercial
devices will probably have a bit more heft for structural stability and ruggedness.
Samsung claims it will be releasing the first commercial model, based on carbon
nanotube emitters, by early 2004.
Other potential job losses could be those of supermarket cashiers if
nanotechnology-based, flexible, thin-film computers housed in plastic product
wrappings enable all-at-once checkout. Supermarket customers could simply
wheel their carts through a detection gateway, similar in shape to the magnetic
security systems found at the exits of stores today. As with any transformative
technology, however, nanotechnology can also be expected to create many new
jobs.
The societal impacts from nanotechnology-based advances in human health care
may also be large. A ten-year increase in human life expectancy in the United
States due to nanotechnology advances would have a significant impact on
Social Security and retirement plans. As in the fields of biotechnology and
genomics, certain development paths in nanotechnology are likely to have ethical
implications.
Nanomaterials could also have adverse environmental impacts. Proper
regulation should be in place to minimize any harmful effects. Because
nanomaterials are invisible to the human eye, extra caution must be taken to
avoid releasing these particles into the environment. Some preliminary studies
point to possible carcinogenic (cancer-causing) properties of carbon nanotubes.
Although these studies need to be confirmed, many scientists consider it prudent
now to take measures to prevent any potential hazard that these nanostructures
may pose. However, the vast majority of nanotechnology-based products will
contain nanomaterials bound together with other materials or components, rather
than free-floating nano-sized objects, and will therefore not pose such a risk.
At the same time, nanotechnology breakthroughs are expected to have many
environmental benefits such as reducing the emission of air pollutants and
cleaning up oil spills. The large surface areas of nanomaterials give them a
significant capacity to absorb various chemicals. Already, researchers at Pacific
Northwestern National Laboratory in Richland, Washington, part of the U.S.
Department of Energy, have used a porous silica matrix with a specially
functionalized surface to remove lead and mercury from water supplies.
Finally, nanotechnology can be expected to have national security uses that
could both improve military forces and allow for better monitoring of peace and
inspection agreements. Efforts to prevent the proliferation of nuclear weapons or
to detect the existence of biological and chemical weapons, for example, could
be improved with nanotech devices.
APPLICATIONS OF NANOTECHNOLGY
Although there has been much hype about the potential applications of
nanotechnology, most current commercialized applications are limited to the use
of "first generation" passive nanomaterials. These include titanium dioxide
nanoparticles in sunscreen, cosmetics and some food products; silver
nanoparticles in food packaging, clothing, disinfectants and household
appliances; zinc oxide nanoparticles in sunscreens and cosmetics, surface
coatings, paints and outdoor furniture varnishes; and cerium oxide nanoparticles
as a fuel catalyst. The Woodrow Wilson Center for International Scholars' Project
on Emerging Nanotechnologies hosts an inventory of consumer products which
now contain nanomaterials.
IMPLICATIONS
The implications of the analysis of such a powerful new technology remain
sharply divided. Nano optimists, including many governments, see
nanotechnology delivering environmentally benign material abundance for all by
providing universal clean water supplies
 atomically engineered food and crops resulting in greater agricultural
productivity with less labour requirements
 nutritionally enhanced interactive ‘smart’ foods
 cheap and powerful energy generation
 clean and highly efficient manufacturing
 radically improved formulation of drugs, diagnostics and organ
replacement
 much greater information storage and communication capacities
 interactive ‘smart’ appliances; and increased human performance through
convergent technologies.
CONCLUSION
The numbers of sectors involved are many, due to multi-disciplinary nature of the
technology, offering scope for numerous opportunities.
Looking at worldwide developments in recent years, it is time India forges a
nanotechnology policy in tune with the specific needs of the country and its
existing strengths.
REFERENCE
[1] Electronics Today
[2]http://en.wikipedia.org/wiki/Nanotechnology
[3]www.cvd.louisville.edu/Research/Nanotech%20Applications/NANO.htm
[4]www.nano.go
[5]www.nanotech-now.com/introduction.htm v/
[6]www.understandingnano.com/introduction.html