NanoTechnology-The Next Science Frontier

8/6/2019 NanoTechnology-The Next Science Frontier

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NanoTechnology-The Next Science Frontier Seminar Report 03

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.

Dept. of EEE M.E.S.C.E., Kuttippuram1


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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



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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.



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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.



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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.



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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 cant 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 Moirs law into the nanoscale will Require

entirely new preparation methods.



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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



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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 Moores law on track until size-dependent properties truly assert

themselves.



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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.



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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.



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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.



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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.



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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.


AFM


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For example, in Atomic Force Microscopy (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 microscopys also exist. They are

referred to as scanning probe microscopys 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.



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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,



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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.



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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.



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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.

Todays 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



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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.



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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.



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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.



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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.



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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



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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.



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REFERENCES

Nanotechnology The Next Big Idea By Mark Ratner

Daniel Ratner

Digit November 2001

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



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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.



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ACKNOWLEDGEMENT

I express my sincere gratitude to Dr. P.M.S. Nambissan, Prof. and

Head, Department of Electrical and Electronics Engineering, MES College of

Engineering, Kuttippuram, for his cooperation and encouragement.

I would also like to thank my seminar guide Ms. Renuka (Lecturer,

Department of EEE), Asst. Prof. Gylson Thomas. (Staff in-charge,

Department of EEE) 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 EEE and

friends for their valuable advice and encouragement.



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CONTENTS

1. INTRODUCTION 1

2. NANOSTRUCTURE 2

3. TOOLS TO MAKE NANOSTRUCTURES 5

4. TOOLS FOR MEASURING THE PROPERTIES OF

NANOSTUCTURES 13

5. APPLICATIONS 17

6. FUTURE APPLICATIONS 23

7. CONCLUSION 24

8. REFERENCES 25

Dept of EEE M E S C E Kuttippuram28

NanoTechnology-The Next Science Frontier

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