nanotechnology-the next science frontier seminar report

NanoTechnology-The Next Science Frontier

NANOTECHNOLOG

Y

-The next science frontier

To,

Ms. SABITHA KUMARI FRANCIS

DEPARTMENT OF ENGLISH

GITAM UNIVERSITY, HYDERABAD

By,V.SANTHOSH KUMAR(2210409157)

&J.KARTHIK REDDY(2210409162)

DEPARTMENT OF ECE,GITAM UNIVERSITY, HYDERABAD


21st FEBRUARY 2011

PREFACE

The field on nanotechnology is still in its infancy but continues to

Progress at a much faster rate than any other field. Many methods to

synthesize nano particles, disperse them in a carrying fluid to form a

composite and exploit its extraordinary properties is the goal and dream

of many researchers engaged in this field. It is not possible to cover

every nano particulate matter and its role in materials revolution. The

approach adopted here was to focus on carbon nanotubes and nano clays

and explore their importance and their role in composites. Hence the

report presented in this material address processing, rheology, mechanical

properties and their interaction with fibre composites.


ACKNOWLEDGEMENT

I express my sincere gratitude to Dr. K.Manjunathachari, Prof. and Head,

Department of Electronics and Communicatin Engineering, Gitam University,

Rudraram, for his cooperation and encouragement.

I would also like to thank my seminar guide Ms.Sabitha Kumari Francis

(Department of English), Asst. Prof. Shyam Sunder Sagar ( Department of ECE)

for their invaluable advice and wholehearted cooperation without which this seminar

would not have seen the light of day.

Gracious gratitude to all the faculty of the department of ECE and friends

for their valuable advice and encouragement.


ABSTRACT

Imagine a supercomputer no bigger than a human cell. Imagine a

four-person, surface-to-orbit spacecraft no larger or more expensive than the

family car. Imagine attaining immortality by drinking a medicine. These are

just a few products expected from Nanotechnology.

Nanotechnology is molecular manufacturing or, more simply,

building things one atom or molecule at a time with programmed

nanoscopic robot arms; Nanotechnology proposes the construction of novel

molecular devices possessing extraordinary properties. The trick is to

manipulate atoms Individually and place them exactly where needed to

produce the desired Structure.

The goal of early nanotechnology is to produce the first nano-sized

robot Arm capable of manipulating atoms and molecules into a useful

product or Copies of itself. Nanotechnology will arrive with the

development of the first "Universal Assembler" that has the ability to build

with single atoms anything one's software defines. This paper deals with the

various possible applications of nanotechnology and the process involved.


CONTENTS

1. PREFACE

2. ACKNOWLEDGEMENT

3. ABSTRACT

4. INTRODUCTION

5. NANOSTRUCTURE

6. TOOLS TO MAKE NANOSTRUCTURES

7. TOOLS FOR MEASURING THE PROPERTIES OF

NANOSTUCTURES

8. APPLICATIONS

9. FUTURE APPLICATIONS

10. CONCLUSION

11. REFERENCES


INTRODUCTION

The industrial revolution, electricity, computers, Internet and now

the next big thing is Nanotechnology. Technically Nanotechnology is

defined as an anticipated manufacturing technique by which one can be

given thorough and inexpensive control over the structure of matter. These

structures are known as nanostructures. The term Nanotechnology was first

introduced by Richard Feynman in 1959 and K Eric Drexler popularized it

in 1986 in the book ‘Engines of Creation’.

It is also defined as the ability by which we can arrange atoms by

given each its place and thus forms the structure in nanometer scale.

Nanotechnology deals with matter at atomic levels. The term nano is derived

from Greek word dwarf. Here it refers to one billionth of a meter or (10-9).

The central thesis of Nanotechnology is that almost all chemically

stable structures that can be specified can also built. Nanotechnology puts

the power of creation in human hands.


NANOSTRUCTURE

Nanostructures must be assembled from some building blocks.

These fundamental building blocks are created from atoms of 91 naturally

occurring elements. It is inefficient to start with individual atoms due to the

slowness and less strength of materials. Usually nanostructures are built,

starting with larger building blocks or molecules as components.

Nanostructures are new semi molecular building blocks to

assemble Nanostructures.Two of these Nanostructures are Nanotubes &

Nanorods that can be made out of silicon, other semiconductors, metals, or

even insulators. These Nanorods are made using clever solution chemistry

methods, but they can then self assemble into larger Nanoscale structures.

Nanotubes and Nanowires

Graphite is used as a lubricant and in pencils. It is formed out of

sheets of carbon atoms linked together hexagonally like chicken wire.

Nanoscientists are very interested in them because when rolled into tubes

they exhibit some amazing properties. These cylinders of graphite are called

carbon Nanotubes.When the roll is only one sheet of carbon atoms thick

they are called single walled carbon Nanotubes. Nanotubes are the first


nanomaterials engineered at the molecular level, and they exhibit physical

and chemical properties that are truly breathtaking.

Carbon NanoTube

Nanotubes show tensile strength greater than 60 times to high-

grade steel. Nanotubes are not only strong but they are also very light and

flexible. They are used in aeroplane design.

Nanotubes show excellent electrical properties. Scientists tested

Nanotubes and found that they behaved like superconductors. Current theory

holds that they can act as either superconductors or semiconductors based

depending on the exact proportions of the tube and which materials other

than carbon are introduced into the tube matrix.


Not all Nanotubes are manufactured out of carbon. Silicon

Nanotubes are also common though Nanotubes of silicon are called as

Nanowires.

Nanotube and Nanowire research are hot topics both for science

and industry. IBM have already used nanotubes to craft usable transistors

with properties exceeding those of their pure silicon cousins and some

nanotubes based logic gates have been produced.


TOOLS TO MAKE NANOSTRUCTURES….

There are mainly two approaches for the development of

Nanostructures. They are:

Top-Down Approach

Bottom-Up approach

Top-down approach is an engineering approach for the

construction of Nanoscopic devices. Here we take a large structure and

divide it into smaller structures iteratively. Bottom-Up approach deals with

building up a Nanostructure by starting from a single atom.

Scanning probe instruments

Creating structures at Nanoscale required them to be manipulated

at Nanoscale.For these various instruments were used .The scanning probe

instruments form the basis of these. Scanning probe instruments cannot only

be used to see Nanostructure but also to manipulate them. The principle is

used as dragging finger. Just as we scratch a soft surface we can modify the

structure. Similarly with the tip of the scanning probe we manipulate the

structure by dragging the tip above the surface.


Scanning probes are used to demonstrate and test some

fundamental scientific concepts ranging through structural chemistry,

electrical interactions and magnetic behaviors.

Scanning probe surface assembly is inherently very elegant, but it

suffers three limitations:

It is relatively expensive

It is relatively slow.

It cannot satisfy mass demand.

Nanoscale Lithography

The word lithography originally referred to making objects from

stones. A lithograph is an image that is produced by carving a pattern on the

stone, inking the stone and then pushing the inked stone onto the paper.

Nanoscale lithography really can’t use visible light because the

wavelength of visible light is at least 400 nanometers, so structures smaller

than that are difficult to make directly using it. This is one of the reasons

that continuing Moiré’s law into the nanoscale will require entirely new

preparation methods.


Dip Pen Nanolithography

One way to construct arbitrary structures on surfaces is to write

them in exactly the same way that we write ink lines using a fountain pen.

To make such lines at the nanoscale it is necessary to have a nanopen.

Fortunately AFM tips are ideal nanopens. Dip pen nanolithography is named

after the old-fashioned dip pen that was used in schoolrooms in the 19th

century. The principle of DPN is shown in the figure.

In DPN a reservoir of ‘ink’ (atoms or molecules) is stored on the

top of the scanning probe tip, which is manipulated across the surface,

leaving lines and patterns behind. Using this technique any complex

structure can be realized because AFM tips are relatively easy to

manupulate. This fact makes DPN the technique of choice for creating new

and complex structures in small volumes the disadvantage of this technique

is that it is very slow.


E-Beam Lithography

We mentioned that current light based industrial lithography is

limited to creating features no smaller than the wavelength used. Even

though we can in principle get around this restriction by using light of

smaller wavelengths, this solution can generate other problems. Smaller-

wavelength light has higher energy, so it can have nasty side effects like

blowing the feature we are trying to create right off the surface.

An alternate way of getting around the problem is to use electrons

instead of light. This E-beam lithography can be used to make structures at

the nanoscale. Figure shows two electrodes that are made using E-beam

lithography to align platinum nanowires. The structure lying across the

nanoscale electrodes is a single molecule, a carbon nanotube.

E-beam lithography also has applications in current

microelectronics manufacturing and is one approach that will be used to

keep Moore’s law on track until size-dependent properties truly assert

themselves.

Nanosphere Liftoff Lithography


If marbles are placed together on a board as tightly as possible,

they will form a tight group with each marble surrounded by six others. If

this array was spray-painted from the top and then the marbles were tipped

off the board. The paint would appear as a set of painted dots each shaped

like a triangle with concave edges. Now if the marbles are nanoscale

marbles, so are the painted dots.

The technique is called nanosphere liftoff lithography.

Importantly, this liftoff nanolithography, unlike DPN or scanning probe but

like nanostamp, is parallel. Many nanosphers can be placed on the surface,

so that regular arrays of many dots can be prepared.

Self-Assembly


The problems with most of the techniques for assembling

nanostructures that we have seen so far is that are too munch like work. It is

glorious if we could just mix chemicals together and get nanostructures by

letting the molecules sort themselves out.

One approach to nanofabrication attempts to do exactly this. It is

called self-asseembly.The idea behind self-assembly is that molecules will

always seek the lowest energy level available to them. If bonding to an

adjacent molecule accomplishes this, they will bond. If reorienting their

physical positions does the trick, then they will reorient. The forces involved

in self-assembly are generally weaker than the bonding forces that hold

molecules together.

They correspond to weaker aspects of Coloumbic interactions and

are found in many places throughout nature. In self-assembly, the nano

builder introduces particular atoms or molecules onto a surface or onto a

preconstructed nanostructure. The molecules then align themselves into

particular positions, sometimes forming weak bonds and sometimes forming

strong covalent ones, inorder to minimize the total energy. One of the huge

advantages of such assembly is that large structures can be prepared in this

way, so it is not necessary to tailor individually the specific nanostructures.

Self-assembly is not limited to electronics applications. Self-

assembled structures can be used for something as mundane as protecting a

surface against corrosion or making a surface slippery, sticky, wet, or dry.


Self-assembly is probably the most important of the nanoscale fabrication

techniques because of its generality, its ability to produce structures at

different length scales, and its low cost.

Nanoscale Crystal Growth

Crystal growth is another sort of self-assembly. Crystals like salt

that are made of ions are called ionic crystals. Those made of atoms are

called atomic crystals, and those made of molecules are called molecular

crystals. So salt is an ionic crystal and sugar is a molecular crystal.

Crystal growth is partly art, partly science. Crystals can be grown

from solution using seed crystals, which involves putting a small crystal into

the presence of more of its component materials and allowing those

components to mimic the pattern of the small crystal or seed. Silicon boules,

the blocks used for making microchips, are made or ‘drawn’ in this way.


Polymerization

Polymers are very large molecules. They can be upward of

millions atoms in size, made by repetitive formation of the bond from one

small molecular unit to the next. Polymerization is a very commonly used

scheme for making nanoscale materials and even much larger ones-epoxy

adhesives work by making extended polymers upon mixing the two

components of the epoxy. Controlled polymerization, in which one

manometer at a time is added to the next, is very important for specific

elegant structures.


TOOLS FOR MEASURING THE PROPERTIES OF

NANOSTUCTURES

Scanning Probe Instruments

Some of the first tools to help launch the nanoscience revolution

were the so-called scanning probe instruments. The idea is a simple one: if

you rub your finger along a surface, it is easy to distinguish velvet from steel

or wood from tar. The different materials exert different forces on your

finger as you drag it along the different surfaces. In these experiments your

finger acts like a force measurement structure. It is easy to slide across a

satin sheet than across warm tar because

the warm tar exerts a stronger force

dragging back the finger. This is the idea

of the scanning force microscope, one of

the common types of scanning probe.

In scanning probe measurements,

the probe, also called a tip, slides along a

surface in the same way your finger does.

The probe is of nanoscale dimensions, often only a single atom in size where

it scans the target. As the probe slides, it can measure several different

properties, each of which corresponds to a different scanning probe

measurement. For example, in Atomic Force Microscopy (AFM),

AFM


electronics are used to measure the force exerted on the probe tip as it moves

along the surface.

In Scanning Tunneling Microscopy (STM), the amount of electric

current flowing between a scanning tip and a surface is measured.

Depending on the way the measurement is done, STM can be used either to

test the local geometry or the local electrical conducting characteristics.

In Magnetic Force Microscopy (MFM). The tip that scans across

the surface is magnetic. It is used to sense the local magnetic structure on the

surface. The MFM tip works in a similar way to the reading head on a hard

disk drive or audio cassette player.

Other types of scanning microscopy’s also exist. They are referred

to as scanning probe microscopy’s because all are based on the general idea

of the STM.In all of them, the important idea is that a nanoscale tip that

slides or scans over the surface is used to investigate nanoscale structure by

measuring forces, currents, magnetic drag, chemical identity, or other

specific properties.


Spectroscopy

Spectroscopy refers to shining light of a specific color on a sample

and observing the absorbtion, scattering or other properties under those

conditions. Spectroscopy is a much older, more general t than scanning

probes microscopy and it offers many complementary insights.

Magnetic Resonance Imaging, or MRI is another type of Spectroscopy that

may be familiar from its medical applications. Many sorts of Spectroscopy

using different energies of light are used in the analysis of nanostructures.

Visible light cannot be used for the spectroscopy analysis of

nanostructures because the wavelength of light is between 400nm and

900nm.So light of lesser wavelength is used for analysis. Spectroscopy is of

great importance for characterising nanostructure en masse, but most types

of Spectroscopy do not tell us about structures on the nanoscale of

nanometers.

Electrochemistry

Electrochemistry deals with how the chemical processes can be

changed by the application of electrical currents, and how electric currents

can be generated from chemical reactions. The most common

Electrochemistry devices are batteries that produce energy from chemical

reactions. The opposite process is seen in electroplating, wherein metals are

made to form on surfaces because positively charged metal ions absorb


electrons from the current flowing through the surface to be neutral plated

and become neural metals.

Electrochemistry is broadly used in the manufacturing of

nanostructure, but it can also be used in their analysis. The nature of the

surface atoms in an array can be measured directly using Electrochemistry,

and advanced electrochemical technique scanning are often used both to

construct and to investigate nanostructures.

Electron Microscopy

These methods are based on the use of electrons rather than light to

examine the structure and behavior of the material. There are different types

of Electron Microscopy, but they are all based on the same general idea.

Electrons are accelerated passed through samples. As the electrons

encounter nuclei and other electrons, they scatter. By collecting the electrons

we can construct an image that describes where the particles were that

scattered the electrons did not make it through. This is called Transmission

Electron Microscopy (TEM).

TEM images can have resolution sufficient to see individual atoms,

but samples must often be stained before they can be imaged. Additionally

TEM can only measure physical structure, not forces like those from

magnetic or electric fields. Still, Electron Microscopy has many uses and is

broadly used in nanostructure analysis and interpretation.


APPLICATIONS

With the development of Nanotechnology it expects to find

applications in various fields. The various applications of Nanotechnology

are:

Nano Computers

Nanotechnology is focusing on projects, which can be

implemented in bettering our lives. Pervasive computing is an area where a

lot of Nanotechnology projects are currently active. If we want to design a

chip to fit into our fingertip controlling a music system then solution lies

with Nanotechnology.

While making a microprocessor we handle big groups of

semiconductor molecules and structure them into the form we need. This

form of handling of matter produces severe limitations as to how small these

circuits can be made. Present day lithographic technologies are at 0.13

microns. After 0.13 microns it is very difficult to etch the circuits precisely

and effectively on the silicon substrate. This is where Nanotechnology steps

in. Nanotechnology offers convenience to bulk technology.


Computing giant IBM has come up with a new kind of memory

using a technology called ‘Millipede Technology’ which makes use of an

array of AFM probes to make marks on a polymer surface for storing data.

Each tip writes a bit of 50nm on the polymer, which stores data.

Today’s best storage devices are capable of storing data up to

2Giga bits per square cm where as Nanotechnology increases the memory to

80Giga bits per square cm using a single AFM tip. The main advantage of

using such technology, other than the small sizes, is the power consumption.

Material Technology

It is another major area, which will be affected by Nanotechnology.

A nanotube is one such innovation, which can change almost all the areas

that we are familiar with. The advantage of using nanotubes is that it is

possible to control the way these crystals are developed for applications.

Electrical and other properties of materials made using nanotubes can be

made to fit precise specifications.

Scientists have begun to mix and match the attractive properties of

certain chemicals to produce materials and fabrics that are stronger or more

resistant. One company has already reengineered cotton with an outer

structure resistant to wrinkles and stains. Nanotubes are also innovations of

material technology, which can suit precise mechanical and electrical

properties.


Medicine

With the development of Nanotechnology we can even replace

operations. The concept used here is ‘Micro encapsulation’ a

Nanotechnology technique, which will help doctors to control precisely the

rate at which medicine, are supplied to patient body. One of the major

medicinal breaks through in the area of Nanotechnology is the discovery of

composite structure of carbon called ‘Bucky balls’ or C60 molecules. Bucky

balls were discovered by Richard Smalley.The main advantage of using

bucky balls are that they are extremely small (1nm long) and non-toxic.

These spherical particles are very smooth. The body easily excretes them,

which make them perfect as drug delivery mechanisms.

Using bucky balls medicines could be delivered to the body orally

and then the body eliminates it without any side effects .It is possible to

attach the needed drugs on the bucky balls. This is much easier and effective

than the conventional capsule approach. In capsules a mixture of drugs is

delivered into the body, a major part of which is eliminated by the body.

Another exciting property that Nanotechnology presents is the

ability to have minute machines traveling inside our body protecting us from

the inside.


These nanodoctors will be able to find and repair damage at the

cellular level. For this to be possible molecular assemblers with better

capabilities than the current STM are needed. Nanorobots are also similar to

Nanodoctors.

The concept of Nanotechnology powered has a long way to go

before it can become a reality. This technology is mainly aimed to treat

cancer cells and sometimes even suggest cures.


Nanoelectronics

Instead of burning features on to a Si chip nanolectronics are built

atom by atom through carefully controlled chemical reactions that will

eventually allow for faster information processing. Nanoelectronics will be

able to down size transistors producing tera scale integrated chips containing

more than a trillion transistors.

Nano LED

This is a novel light source system that uses LED to produce a

pulse of 50pico sec to 2nano sec between wavelength of 370nm and

660nm.Today nanoled emits blue, red, UV, amber light.

Applications of Nano LED

Illumination: It is highly efficient than conventional light build, it

consumes only 15 watts compared to traditional traffic lights which

consume 150 watts and so can be used for traffic lights which are expected

to burn for more than a decade continuously. More over they are compact,

have low power consumption and low heat.


Replacement of Flash lamps: Flash lamps which are heavier and cost more

will be replaced by Nano LED in their applications because of their low cost

and portability.

Sensors: Sensors are highly sensitive systems that can be used to warn of

presence of chemicals in air or water. Nano LED is more flexible than

conventional sensors because the chemical substance can alter the surface

structure of LED.

In Computing and electronic devices: Further miniaturization in

circuits is done to increase processing power and speed of devices. It can be

used in Nanodevices where Ultra fast clocks are required for faster

computation and for running the device at rates greater than 1GHz.

Optical Devices: Nano LED based on silicon is used in telecommunication

industry for long and medium range data transmission via glass optical

fibres by conducting pulses of laser light.


FUTURE APPLICATIONS

Scientist are just beginning to explore and manipulate the inner

workings of an atomic universe using Nanotechnology, the crucial

convergence of biology, chemistry and electronics that is poised to

revolutionize science.

In future with the invention of Robotic arm Nanotechnology will

evolve into reality. The applications of Nanotechnology in future are

expected to be in the areas of:

Medicine

Environmental

Robotics

Nano Electronics

Material Innovations

Pharmaceuticals

IT field


CONCLUSION

Many of the concepts that Nanotechnology presents may look

impossible now but they may not be so far away. Nanotechnology is nearer

than we can think. The Nano storm will catch us quietly. The only difference

being that it will come in a silent subdued manner much like how we used

and embraced artificial fibres over the years without knowing it & it will

make a tremendous impact on our lives.


REFERENCES

Nanotechnology – The Next Big Idea By Mark Ratner

Daniel Ratner

Presentation from www.google.co.in

www.nanotechnology.com

Web.me.unr.edu/me372/Spring2001/Nanotechnology.pdf

nanotechnology-the next science frontier seminar report

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