# Nanotechnology/Perspective#Nanocomponents.2C Tools.2C and Methods

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# A perspective on Nanotechnology

**Nanotechnology in the Middle Ages?**

The Duke TIP eStudies Nanotechnology course will be adding more to this
section (this will be completed by 22 Jun 08)

One of the first uses of nanotechnology was in the Middle Ages. It was
done by using gold nanoparticles to make red pigments in stained glass
showing that nanotechnology has been around for centuries. The gold when
clumped together appears gold, but certain sized particles when spread
out appear different colors. Reference: The Nanotech Pioneers Where are
they taking us? By Steven A Edwards

In the year 1974 at the Tokyo Science University, Professor Norio
Taniigrichi came up with the term
nanotechnology.

Nanotechnology was first used to describe the extension of traditional
silicon machining down into regions smaller than one micron (one
millionth of a meter) by Tokyo Science University Professor Norio
Taniguchi in 1974. It is now commonly used to describe the engineering
and fabrication of objects with features smaller than 100 nanometers
(one tenth of a micron). [^1]

Nanotechnology has been used for thousands of years, although people did
not know what they were doing. For example, stained glass was the
product of nanofabrication of gold. Medieval forgers were the first
nanotecnologists in a sense, because they, by accident, found out a way
to make stained glass.

Reference Nanotechnology A GENTLE INTRODUCTION TO THE NEXT BIG IDEA By
Mark Ratner & Daniel Ratner

In 2001, the federal government announced the National Nanotechnology
Intiative to coordinate the work of different U.S. agencies and to
provide funds for research and accelerate development in nanotechnology.
This was spearheaded by Mahail Roco and supported by both president
Clinton and Bush.

References The Nanotech Pioneers Where are they taking us? By Steven A.
Edwards
<http://www.nano.gov/html/about/docs/20070521NNI_Industrial_Nano_Impact_NSTI_Carim.pdf>

**A Vision**

Richard Feynman was a man of great importance to the field of
nanotechnology. He was a man with a vision. He believed that with
research we could change things on a small scale. In his famous speech
There\'s Plenty of Room at the
Bottom in 1959,  Richard
Feynman discussed the possibility of
manipulating and controlling things on a molecular scale in order to
achieve electronic and mechanical systems with atomic sized components.
He concluded that the development of technologies to construct such
small systems would be interdisciplinary, combining fields such as
physics, chemistry and biology, and would offer a new world of
possibilities that could radically change the technology around us.

**Miniaturization**

A few years later, in 1965,  Moore
noted that the number of transistors on a chip had roughly doubled every
other year since 1959, and predicted that the trend was likely to hold
as each new generation of microsystems
would help to develop the next generation at lower prices and with
smaller components. To date, the semiconductor industry has been able to
fulfill Moore\'s Law, in part through the reduction of lateral feature
sizes on silicon chips from around 10 micrometers in 1965 to 45-65 nm in
2007 via changing from the use of optical contact lithography to deep
ultraviolet projection lithography.

In 1974 in Japan, Norio Taniguchi coined the word \"nano-technology\"
[^2] to describe semiconductor processes such as thin film deposition
and ion beam milling exhibiting characteristic control on the order of a
nanometer: \"'Nano-technology' mainly consists of the processing of
separation, consolidation, and deformation of materials by one atom or
one molecule.\"

Since Feynman\'s 1959 speech the arts of \"seeing\" and \"manipulation\"
at the nanoscale have progressed from transmission electron microscopy
(TEM) and scanning electron microscopy (SEM) to various forms of
scanning probe microscopy including scanning tunneling microscopy
(STM) developed by Binnig and Rohrer
at IBM Zurich and atomic force microscopy
(AFM) devloped by (Binnig and Quate?)
The STM, in particular, is capable of single-atom manipulation on
conducting surfaces and has been used to build \"quantum corrals\" of
atoms in which quantum mechanical wave function phenomena can be
discerned. These atomic-scale manipulation capabilities prompt thoughts
of building up complex atomic structures via manipulation rather than
traditional stochastic chemistry. (Note: this pragraph is still rough
and references are needed.)

Motivated by Feynman's beliefs building things nanoscale top-down, Eric
Drexler devoted much of his research to making a universal assembler.
The American engineer  Eric Drexler has
speculated extensively about the laboratory synthesis of machines at the
molecular level via manipulation techniques, emulating biochemistry and
producing components much smaller than any microprocessor via techniques
which have been called molecular
nanotechnology or MNT. [^3] [^4]
[^5]

Successful realization of the
MNT dream would comprise a
collection of technologies which are not currently practical, and the
dream has resulted in considerable hyperbolic description of the
resulting capabilities. While realization of these capabilities would be
a vindication of the hype associated with MNT, concrete plans for
anything other than computer modeling of finished structures are scant.
Somehow, a means has to be found for MNT design evolution at the
nanoscale which mimics the process of biological evolution at the
molecular scale. Biological evolution proceeds by random variation in
ensemble averages of organisms combined with culling of the
less-successful variants and reproduction of the more-successful
variants, and macroscale engineering design also proceeds by a process
of design evolution from simplicity to complexity as set forth somewhat
satirically by John Gall: \"A
complex system that works is invariably found to have evolved from a
simple system that worked. . . . A complex system designed from scratch
never works and can not be patched up to make it work. You have to start
over, beginning with a system that works.\" \<ref name=\"JohnGall\>
Gall, John, (1986) Systemantics: How Systems Really Work and How They
Fail, 2nd ed. Ann Arbor, MI : The General Systemantics Press.

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A breakthrough in MNT is needed
which proceeds from the simple atomic ensembles which can be built with,
e.g., an STM to complex
MNT systems via a process of
design evolution. A handicap in this process is the difficulty of seeing
and manipulation at the nanoscale compared to the macroscale which makes
deterministic selection of successful trials difficult; in contrast
biological evolution proceeds via action of what Richard Dawkins has
called the \"blind watchmaker\" [^6] comprising random molecular
variation and deterministic survival/death.

**Technological development and limits**

The impact on society and our lives of the continuous downscaling of
systems is profound, and continues to open up new frontiers and
possibilities. However, no exponential growth can continue forever, and
the semiconductor industry will eventually reach the atomic limit for
downsizing the transistor. Atoms in solid matter are typically one or
two hundred picometers apart so nanotechnology involves manipulating
individual structures which are between ten and ten thousand atoms
across; for example, the gate length of a 45 nm transistor is about 180
silicon atoms long. Such very small structures are vulnerable to
molecular level damage by cosmic rays, thermal activity, and so forth.
The way in which they are assembled, designed and used is different from
prior microelectronics.

**New ways**

Today, as that limit still seems to be some 20 years in the future, the
growth is beginning to take new directions, indicating that the atomic
limit might not be the limiting factor for technological development in
the future, because systems are becoming more diverse and because new
effects appear when the systems become so small that quantum effects
dominate. The semiconductor devices show an increased diversification,
dividing for instance processors into very different systems such as
those for cheap disposable chips, low power consumption portable
devices, or high processing power devices. Microfabrication is also
merging with other branches of science to include for instance chemical
and optical micro systems. In addition, microbiology and biochemistry
are becoming important for applications of all the developing methods.
This diversity seems to be increasing on all levels in technology and
many of these cross-disciplinary developments are linked to
nanotechnology.

**Diversification**

As the components become so small that quantum effects become important,
the diversity will probably further increase as completely new devices
and possibilities begin to open up that are not possible with the bulk
materials of today\'s technology.

**The nanorevolution?**

The visions of Feynman are today shared by many others: when
nanotechnology is seen as a general cross disciplinary technology, it
has the potential to create a coming \"industrial\" revolution that will
have a major impact on society and everyday life, comparable to or
exceeding the impact of electricity and information technology.

# Nanocomponents, Tools, and Methods

**A positive spiral**

As an emerging technology, the methods and components of nanotechnology
are under continuous development and each generation is providing a
better foundation for the following generation.

**Seeing \'nano\'**

With regards to the methods, the  Scanning tunneling microscope
(STM) and  Atomic Force
Microscope (AFM) were developed
in the 1980s and opened up completely new ways to investigate nanoscale
materials. An important aspect was the novel possibility to directly
manipulate nanoscale objects. Transmission and scanning electron
microscopes (TEM and
SEM) had been available
since the 30s, and offered the possibility to image as well as create
nanodevices by electron beam
lithography.

**New nanomaterials**

Several unique nanoscale structures were also discovered around 1990:
the  Carbon-60 molecule and later the  carbon
nanotubes. In recent years, more complex
nanostructures such as  semiconductor nanowire
heterostructures have also proven to be useful building blocks or
components in nanodevices.

**So what can I use this \'nano\' for?**

The applications of such nanocomponents span all aspects of technology:
Electronics, optics/photonics, medical, and
biochemical, as well as better and smarter materials. But to date few
real products are available with nanoscale components, apart from
traditional nanoscale products, such as paint with nanoparticles or
catalytic particles for chemical reactors.

Prototype devices have been created from individual nanocomponents, but
actual production is still on the verge. As when integrated electronics
were developed, nanotechnology is currently in the phase where component
production methods, characterization methods, tools for manipulation and
integration are evolving by mutual support and convergence.

**Difficult nanointegration**

A main problem is reliable integration of the nanoscale components into
microsystems, since the production methods
are often not compatible. For fabrication of devices with integrated
nanocomponents, the optimal manipulation technique is of course to have
the individual components self-assembling or growing into the required
complex systems. Self assembly of devices in liquids is an expanding
field within nanotechnology but usually requires the components to be
covered in various surfactants, which usually also influence the
component properties. To avoid surface treatments, nanotubes and
whiskers/wires can be grown on chips and
microsystems directly from pre-patterned
catalytic particles. Although promising for future large scale
production of devices, few working devices have been made by the method
to date.

The prevailing integration technique for nanowire/tube systems seems to
be  electron beam lithography
(EBL) of metal structures onto
substrates with randomly positioned nanowires deposited from liquid
dispersions. By using flow alignment or electrical fields, the wire
deposition from liquids can be controlled to some extent. The EBL method
has allowed for systematic investigations of nanowires\' and tubes\'
electrical properties, and creation of high performance electronic
components such as field-effect transistors and chemical sensors. These
proof-of-principle devices are some of the few but important
demonstrations of devices nanotechnology might offer. In addition,
nanomechanical structures have also recently been demonstrated, such as
a rotational actuator with a carbon nanotube axis built by Fennimore et
al.

A more active approach to creating nanowire structures is to use 
Scanning probe microscopy(SPM)
to push, slide and roll the nanostructures across surfaces. SPM
manipulation has been used to create and study nanotube junctions and
properties. The ability to manipulate individual nanoscale objects has
hence proven very useful for building proof-of-principle devices and
prototypes, as well as for characterizing and testing components.

**Top-down manufacturing** takes bulky products and shrinks them to the
nano scale, vs. bottom-up manufacturing is when individual molecules are
placed in a specific order to make a product.[^7] The **bottom-up
self-assembly** method may be important for future large scale
production as well as many of the different approaches to improve the
top-down lithographic processes. Such techniques could hence become
important factors in the self-sustaining development of nanotechnology.

# Hot and hyped

**Suddenly everything is \'nano\'**

There\'s no question that the field of nanotechnology has quite a sense
of hype to it - many universities have created new nanotech departments
and courses. But there is also a vision behind the hype and emerging
results - which are truly very few in industrial production, but
nevertheless hold promise for a bright future. In the hype, many things
that were once chemistry, microtechnology,
optics, mesoscopic or cluster physics, have been
reborn as nanotechnology.

**Nanotech is old**

You can find nanotechnology in the sunscreen you use in the summer, and
some paints and coatings can also be called nanotech since they all
contain nanoparticles with unique optical properties. In a way,
nanoparticles have been known in optics for
hundreds of years if you like to take a broad perspective on things,
since they have been used to stain and color
glasses, etc. since the middle ages.
Nano-size particles of gold were used to create red pigments.[^8]

Catalysis is a major industrial process,
without which not many of the materials we have around us today would be
possible to make, and catalysis is often highly dependent on nanoscale
catalytic particles. In this way thousands of tons of nanotechnology
have been used with great benefit for years.

Nanoscale wires and tubes have only recently really been given attention
with the advent of carbon nanotubes and
semiconductor nanowires, while nanoscale films are ever present in
antireflection coatings on your glasses and binoculars, and thin metal
films have been used for sensitive detection with surface
plasmons for decades. Surface
plasmons are excitations of the charges at a surface. Nanowires actually
were observed in the middle ages - well, they did not have the means to
observe them, but saw whiskers grow from melted metals.

The better control over the nanostructure of materials has led to
optimization of all these phenomena - and the emergence of many new
methods and possibilities.

**An example**

Take for instance nano-optics: The surface plasmons turn out to be very
efficient at enhancing local electrical fields and work as a local
amplifier for optical fields, making a laser seem much more powerful to
atoms in the vicinity of the surface plasmon. From this comes the
surface enhanced raman spectroscopy
which is increasingly used today because it makes it possible to do
sensitive raman spectroscopy on the large majority of samples that would
otherwise be impossible to make such spectra on. In addition,  photonic
crystals, fancy new quantum light
sources that can make single photons on demand and other non-classical
photon states are being developed, based on nanotechnology.

**The future**

There are definitely future scientific applications and commercial
potential of all these new methods to handle light, use it for extremely
sensitive detection and control its interaction with matter - and so it
seems nanotechnology, being about making smaller versions of existing
technology as well as new technology, is worth a bit of hype.

# References

See also notes on editing this book
Nanotechnology/About#How_to_contribute.
.

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[^1]:
    
[^2]: N. Taniguchi, \"On the Basic Concept of \'Nano-Technology\',\"
    Proc. Intl. Conf. Prod. Eng. Tokyo, Part II, Japan Society of
    Precision Engineering, 1974.

[^3]: Steven A. Edwards, *The Nanotech Pioneers*, (WILEY-VCH, 2006)

[^4]: Eric Drexler, *Engines of Creation*, (New York: Anchor
    Press/Doubleday, 1986).

[^5]: Eric Drexler, *Nanosystems: Molecular Machinery, Manufacturing and
    Computation*, (New York: John Wiley, 1992).

[^6]: Richard Dawkins, The Blind Watchmaker: Why the Evidence of
    Evolution Reveals a Universe Without Design, W. W. Norton; Reissue
    edition (September 19, 1996)

[^7]: Eric Drexler, *Engines of Creation*

[^8]: Nanotech Pioneers, Steven A. Edwards (WILEY-VCH, 2006, Weinheim)
