NANO TECHNOLOGY

 

 

 

 

 

NANO TECHNOLOGY

 

CONTENTS

 

o   INTRODUCTION

o   NANOTECHNOLOGY

o   NANO MATERIALS

o   ORIGINS

o   CURRENT SEARCH

o   TOOLS AND TECHNIQUES

o   APPLICATION

o        REFERENCE
INTRODUCTION

Nanotechnology (sometimes shortened to "nanotech") is the manipulation of matter on an atomic and molecular scale. Generally, nanotechnology works with materials, devices, and other structures with at least one dimension sized from 1 to 100 nanometres. Quantum mechanical effects are important at this quantum-realm scale. Nanotechnology is a key technology for the future and governments have invested billions of dollars in its future. Through its National Nanotechnology Initiative, the USA has invested 3.7 billion dollars. The European Union has invested 1.2 billion and Japan 750 million dollars.

Nanotechnology is very diverse, ranging from extensions of conventional device physics to completely new approaches based upon molecular self-assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale. Nanotechnology entails the application of fields of science as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, microfabrication, etc.

Scientists debate the future implications of nanotechnology. Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biomaterials and energy production. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of nanomaterials, and their potential effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups and governments on whether special regulation of nanotechnology is warranted.

Nanomaterials

The nanomaterials field includes subfields which develop or study materials having unique properties arising from their nanoscale dimensions.

 Interface and colloid science has given rise to many materials which may be useful in nanotechnology, such as carbon nanotubes and other fullerenes, and various Nan particles. Nanomaterials with fast ion transport are related also to nanoionics and Nan electronics.

Nanoscale materials can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor.

·                     Progress has been made in using these materials for medical applications; see Nanomedicine.

·                     Nanoscale materials are sometimes used in solar cells which combats the cost of traditional Silicon solar cells

·                     Development of applications incorporating semiconductor Nan particles to be used in the next generation of products, such as display technology, lighting, solar cells and biological imaging; see quantum dots.

NANOTECHNOLOGY

Nanotechnology, or nanotech, is the study and design of machines on the molecular and atomic level. To be considered nanotechnology, these structures must be anywhere from 1 to 100 nanometers in size. A nanometer is equivalent to one-billionth of a regular meter, which means that these structures are extremely small.

Researcher K. Eric Drexler was the first person to popularize this technology in the early 1980’s. Drexler was interested in building fully functioning robots, computers, and motors that were smaller than a cell. He spent much of the 80’s defending his ideas against critics that thought this technology would never be possible.

Today, the word nanotechnology means something a bit different. Instead of building microscopic motors and computers, researchers are interested in building superior machines atom by atom. Nanotech means that each atom of a machine is a functioning structure on its own, but when combined with other structures, these atoms work together to fulfill a larger purpose.

The U.S. National Nanotechnology Initiative has large plans for nanotech. Mihail Roco, who is involved in this organization, explains the group’s future plans by dividing their goals into four generations.

The first generation of nanotech is defined by passive structures that are created to carry out one specific task. Researchers are currently in this generation of the technology. The second generation will be defined by structures that can multitask. Researchers are currently entering this generation and hoping to further their abilities in the near future. The third generation will introduce systems composed of thousands of nanostructures. The last generation will be defined by Nan systems designed on the molecular level. These systems will work like living human or animal cells.

As nanotech continues to develop, consumers will see it being used for several different purposes. This technology may be used in energy production, medicine, and electronics, as well as other commercial uses. Many believe that this technology will also be used militarily. Nanotechnology will make it possible to build more advanced weapons and surveillance devices. While these uses are not yet possible, many researchers believe that it is only a matter of time.

·                     Nanotechnology basics, news, and general information

Welcome to the world's most in-depth, online resource for the global economy's fastest growing information and investment sector.

We offer consulting, technology monitoring, and in-depth analysis, as well as up-to-the-minute news briefs and breaking developments in the nanosciences. The world's leading nanotech experts routinely contribute to Nanotechnology Now, which has become the daily 'must read' site for stakeholders: inventors, investors, policy makers and opinion shapers.

We are your resource for:

·                     Reporting on disruptive technologies (such as Artificial Intelligence, NEMS, MEMS, Nanoscale Materials, Molecular Manufacturing, Quantum Computing, Nanomedicine, Nanoelectronics, Nanotubes, Self Assembly, and Molecular Biology)

·                     New developments in nanotech inventions, patents, and patent applications

·                     White papers, interviews with industry leaders, and in-depth analysis

·                     Full-service consulting

·                     Investment opportunities in nanotech

·                     Opportunities for venture capitalists

·                     Late breaking news and industry updates

Definition of nano technology

So what exactly is nanotechnology? One of the problems facing nanotechnology is the confusion about its definition. Most definitions revolve around the study and control of phenomena and materials at length scales below 100 nm and quite often they make a comparison with a human hair, which is about 80,000 nm wide. Some definitions include a reference to molecular systems and devices and nanotechnology 'purists' argue that any definition of nanotechnology needs to include a reference to "functional systems". The inaugural issue of Nature Nanotechnology asked 13 researchers from different

Areas what nanotechnology means to them and the responses, from

Theistic to sceptical, reflect a variety of perspectives.

Human hair fragment and a network of single-walled carbon nanotubes)

It seems that a size limitation of nanotechnology to the 1-100 nm range, the area where size-dependant quantum effects come to bear, would exclude numerous materials and devices, especially in the pharmaceutical area, and some experts caution against a rigid definition based on a sub-100 nm size.

Another important criterion for the definition is the requirement that the nano-structure is man-made. Otherwise you would have to include every naturally formed biomolecule and material particle, in effect redefining much of chemistry and molecular biology as 'nanotechnology.'

The most important requirement for the nanotechnology definition is that the nano-structure has special properties that are exclusively due to its nanoscale proportions.

ORIGINS

 

Buckminsterfullerene C₆₀, also known as the buckyball, is a representative member of the carbon structures known as fullerenes. Members of the fullerene family are a major subject of research falling under the nanotechnology umbrella.

Main article: History of nanotechnology

Although nanotechnology is a relatively recent development in scientific research, the development of its central concepts happened over a longer period of time. The emergence of nanotechnology in the 1980s was caused by the convergence of experimental advances such as the invention of the scanning tunneling microscope in 1981 and the discovery of fullerenes in 1985, with the elucidation and popularization of a conceptual framework for the goals of nanotechnology beginning with the 1986 publication of the book Engines of Creation.

The scanning tunneling microscope, an instrument for imaging surfaces at the atomic level, was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory, for which they received the Nobel Prize in Physics in 1986 Fullerenes were discovered in 1985 by Harry Kroto, Richard Smalley, and Robert Curl, who together won the 1996 Nobel Prize in Chemistry

Around the same time, K. Eric Drexler developed and popularized the concept of nanotechnology and founded the field of molecular nanotechnology. In 1979, Drexler encountered Richard Feynman's 1959 talk "There's Plenty of Room at the Bottom". The term "nanotechnology", originally coined by Norio Taniguchi in 1974, was unknowingly appropriated by Drexler in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, which proposed the idea of a nanoscale "assembler" which would be able to build a copy of itself and of other items of arbitrary complexity .Drexler's vision of nanotechnology is often called "Molecular Nanotechnology" (MNT) or "molecular manufacturing," and Drexler at one point proposed the term "zettatech" which never became popular.

CURRENT RESEARCH

Graphical representation of a rotaxane, useful as a molecular switch.

This DNA tetrahedron is an artificially designed nanostructure of the type made in the field of DNA nanotechnology. Each edge of the tetrahedron is a 20 base pair DNA double helix, and each vertex is a three-arm junction.

This device transfers energy from nano-thin layers of quantum wells to nanocrystals above them, causing the nanocrystals to emit visible light.

TOOLS AND TECHNIQUES

                                                                                                                                          Typical AFM setup. A micro fabricated cantilever with a sharp tip is deflected by features on a sample surface, much like in a phonograph but on a much smaller scale. A laser beam reflects off the backside of the cantilever into a set of photodetectors, allowing the deflection to be measured and assembled into an image of the surface.

There are several important modern developments. The atomic force microscope (AFM) and the Scanning Tunneling Microscope (STM) are two early versions of scanning probes that launched nanotechnology. There are other types of scanning probe microscopy, all flowing from the ideas of the scanning confocal microscope developed by Marvin Minsky in 1961 and the scanning acoustic microscope (SAM) developed by Calvin Quate and coworkers in the 1970s, that made it possible to see structures at the nanoscale.

The tip of a scanning probe can also be used to manipulate nanostructures (a process called positional assembly). Feature-oriented scanning methodology suggested by Bratislava Lapshin appears to be a promising way to implement these Nan manipulations in automatic mode. However, this is still a slow process because of low scanning velocity of the microscope.

Various techniques of nanolithography such as optical lithography, X-ray lithography dip pen nanolithography, electron beam lithography or Nan imprint lithography were also developed. Lithography is a top-down fabrication technique where a bulk material is reduced in size to nanoscale pattern.

Another group of Nan technological techniques include those used for fabrication of nanotubes and nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. However, all of these techniques preceded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology and which were results of nanotechnology research.

The top-down approach anticipates nanodevices that must be built piece by piece in stages, much as manufactured items are made. Scanning probe microscopy is an important technique both for characterization and synthesis of nanomaterials. Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface with scanning probe microscopy techniques. At present, it is expensive and time-consuming for mass production but very suitable for laboratory experimentation.

In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly and positional assembly. Dual polarizations interferometry is one tool suitable for characterisation of self assembled thin films. Another variation of the bottom-up approach is molecular beam epitaxy or MBE. Researchers at Bell Telephone Laboratories like John R. Arthur. Alfred Y. Cho and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. MBE allows scientists to lay down atomically precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of spintronics.

APPLICATIONS

One of the major applications of nanotechnology is in the area of Nan electronics with MOSFET's being made of small nanowires ~10 nm in length. Here is a simulation of such a nanowire.

As of August 21, 2008, the Project on Emerging Nanotechnologies estimates that over 800 manufacturer-identified nanotech products are publicly available, with new ones hitting the market at a pace of 3–4 per week. The project lists all of the products in a publicly accessible online database. Most applications are limited to the use of "first generation" passive nanomaterials which includes titanium dioxide in sunscreen, cosmetics, surface coatings, and some food products; Carbon allotropes used to produce gecko tape; silver in food packaging, clothing, disinfectants and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst.

Further applications allow tennis balls to last longer, golf balls to fly straighter and even bowling balls to become more durable and have a harder surface. Trousers and socks have been infused with nanotechnology so that they will last longer and keep people cool in the summer. Bandages are being infused with silver Nan particles to heal cuts faster. Cars are being manufactured with nanomaterials so they may need fewer metals and less fuel to operate in the future. Video game consoles and personal computers may become cheaper, faster, and contain more memory thanks to nanotechnology. Nanotechnology may have the ability to make existing medical applications cheaper and easier to use in places like the general practitioner's office and at home.

CONCLUSIONS

The phrase ‘risks of nanotechnology to man and the environment’ covers a very broad spectrum of research. It is important to bear in mind that there is no such thing as the risks of nanotechnology. The risks depend on the type of nonmaterial (form, size, et cetera), the application method and exposure, and the area of application, et cetera. Therefore we must speak of the acknowledged and potential risksof certain types of nanomaterials in specific situations and applications. Research and debate on the actual and potential risks posed by nanotechnology to humans and the environment currently focus only on first generation nanomaterials; this report too. Here the concern,

Quite rightly, is with manufactured, free, non-degradable and insoluble Nan particles. A great deal still remains unknown about the risks posed by these particles. To learn more about this, a good starting point would appear to be the way in which chemical substances in non-nano form are assessed.

Key considerations for the coming years should be:

• Increasing and exchanging information and knowledge

• Identifying solution areas and risk management

• Making decisions

• Research & Development

• Cooperation

REFERENCES:

References

http://www.cjmag.co.jp/online/0597wnanites.html http://www.imm.org/SciAmDebate2/whitesides.html http://www.smalltimes.com/document_display.cfm?document_id=5148

http://www.def-logic.com/articles/nanomachines.html http://www.ewh.ieee.org/r10/bombay/news3/page4.html http://www-lmr.usc.edu/~lmr/html/research.html http://ipga.phys.ucl.ac.uk/research/bun/index1.htm http://www.capemalta.net/news/Feature%205%20-%20NANOROBOTS.html

http://bionano.rutgers.edu/or.html http://discuss.foresight.org/critmail/sci_nano.88-94/2779.html