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Introduction to Nanotechnology

- History, Definition, Methodology,

Applications, and Challenges

Instructor: Dr. Yu-Bin Chen

Date: 07/25/2012

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Nanoscale Engineering Radiation Lab2

Outline

History

Definition

Methodology

Applications Challenges, Risks, and Ethics

Outline

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Limitations of the Macroscopic Formulation

History

0

limV

m

V

Local density

Constant?

V

Density is not a constant and fluctuates with time even at macroscopic

equilibrium.

When the dimension is comparable with or smaller than that of the

mechanistic length, such as molecular mean free path, the continuum

assumption will break down.

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Theres Plenty of Room at the Bottom

History

by Richard P. Feynman

Full contents of the lecture has been downloaded and posted in

our website as well. Please read what Feynman could view at the

end of 1959 about micro/nanotechnology.

Other useful information about micro/nanotechnology can also be

found in http://www.zyvex.com/nano/

The Nobel Prize in Physics 1965

http://www.zyvex.com/nanotech/feynman.html

Why cannot we write the entire 24 volumes ofthe Encyclopaedia Bri ttanica on the head of a

pin?

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Nanoscale Engineering Radiation Lab

The Development History of Nanotechnology

6

1959

Feynman gives after-dinner talk describing molecular machines building with atomic precision

1974

Taniguchi uses term "nano-technology" in paper on ion-sputter machining

1981First technical paperon molecular engineering to build with atomic precision

STM invented

1985

Buckyball discovered

1986

AFM invented1989

IBM logo spelled in individual atoms

1991

Carbon nanotube discovered

1997

First company founded: Zyvex

2000

President Clinton announces U.S. National Nanotechnology Initiative

2011

First programmable nanowire circuits for nanoprocessors

DNA molecular robots learn to walk in any direction along a branched track

Mechanical manipulation of silicon dimers on a silicon surface

History

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Outline

History

Definition

Methodology


Outline

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Nanometer A nanometre (American spelling: nanometer; symbol nm) is a unit oflength in the

metric system, equal to one billionth of a metre. The name combines the SI prefix

nano- (from theAncient Greek , nanos, "dwarf") with the parent unit name

metre (from Greek , metr

n, "unit of measurement").

The nanometre is often used to express dimensions on the atomic scales: the

diameter of a helium atom, for example, is about 0.1 nm, and that of a ribosome is

about 20 nm. In these uses, the nanometre appears to be supplanting the other

common unit for atomic scale dimensions, the angstrom, which is equal to 0.1nanometre.

Definition

http://en.wikipedia.org/wiki/Nanometre

12,756 km 1.3 cm

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Nanoscale vs. Microscale

Definition

Z. M. Zhang, Nano/Microscale Heat Transfer, 2007.

Dr. Chens research interests

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National Nanotechnology Initiative (NNI)Nanotechnology Definition

Research and technology development at the atomic, molecular or

macromolecular levels, in the length scale of approximately 1 - 100 nanometer

range, to provide a fundamental understanding of phenomena and materials at the

nanoscale and to create and use structures, devices and systems that have novel

properties and functions because of their small and/or intermediate size. The

novel and differentiating properties and functions are developed at a critical length

scale of matter typically under 100 nm.

Nanotechnology research and development includes manipulation under control of

the nanoscale structures and their integration into larger material components,

systems and architectures. Within these larger scale assemblies, the control and

construction of their structures and components remains at the nanometer scale. In

some particular cases, the critical length scale for novel properties and phenomena

may be under 1 nm or be larger than 100 nm.

Definition

http://www.nano.gov

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Limitations of the Macroscopic Formulation

Definition

Inappropriate definition for temperature: Temperature can only be

defined for stable-equilibrium states. That is, extremely high

temperature gradient and/or during very short time periods of time, the

local equilibrium may be inappropriate.

Reduction of thermal conductivity: Thermal conductivity will be

reduced for thin films or narrow wires due to boundary scattering.

Electron and photon tunneling: Electrons and photons cantransport through a very narrow gap.

Surface forces superiority: Surface forces scale down with L2 while

the volume forces scale down with L3.

Better catalyst: The large exposing area of nanoscale particles canboost the catalysis.

Magnetic storage: The nanoscale Fe, Co, and Ni alloy has strong

magnetization ideal for data storage.

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Nanoscience and NanotechnologyRelated Journals (66 total)

Rank Abbreviated Journal Title I F

1 NAT NANOTECHNOL 27.270

2 NANO TODAY 15.355

3 ADV MATER 13.877

4 NANO LETT 13.198

5 ACS NANO 10.774

6 ADV FUNCT MATER 10.179

7 SMALL 8.349

8 NANO RES 6.970

9 NANOMED-NANOTECHOL 6.69210 J PHYS CHEM LETT 6.213

Rank Abbreviated Journal Title I F

11 NANOSCALE 5.914

12 NANOTOXICOLOGY 5.758

13 LAB CHIP 5.670

14 BIOSENS BIOELECTRON 5.602

15 WIRES NANOMED NANOBI 5.186

16 NANOMEDICINE-UK 5.055

17 J PHYS CHEM C 4.805

18 ACS APPL MATER INTER 4.525

19 J BIOMED NANOTECHNOL 4.21620 NANOTECHNOLOGY 3.979

Definition

ESI Web of Science (2011 Report)

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Nanotechnology Resources in Taiwan

Nano Science

Definition

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Outline

History

Definition

Methodology


Outline

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Scanning Electron Microscopy (SEM)

15

Methodology

http://en.wikipedia.org/wiki/File:Schema_MEB_(en).svg

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Transmission Electron Microscopy (TEM)

16

Methodology

http://en.wikipedia.org/wiki/File:Scheme_TEM_en.svg

Transmission electron microscopy

(TEM) is a microscopy technique whereby

a beam ofelectrons is transmitted through

an ultra thin specimen, interacting with thespecimen as it passes through. An image

is formed from the interaction of the

electrons transmitted through the specimen;

the image is magnified and focused onto

an imaging device, such as a fluorescent

screen, on a layer ofphotographic film, or

to be detected by a sensor such as a CCD

camera.

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Scanning Probe Microscopy (SPM)

17

Methodology

Scanning probe microscopy (SPM) is a branch of

microscopy that forms images of surfaces using a physicalprobe that scans the specimen. An image of the surface is

obtained by mechanically moving the probe in a raster

scan of the specimen, line by line, and recording the

probe-surface interaction as a function of position. SPMwas founded with the invention of the scanning tunneling

microscope in 1981. The SPM has multiple types,

including AFM, NSOM(SNOM), and so on.

http://en.wikipedia.org/wiki/Scanning_probe_microscopy

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Atomic Force Microscopy (AFM)

18

Methodology

The AFM consists of a cantileverwith a

sharp tip (probe) at its end that is used to

scan the specimen surface. The cantilever

is typically silicon orsilicon nitride with a tipradius of curvature on the order of

nanometers. When the tip is brought into

proximity of a sample surface, forces

between the tip and the sample lead to a

deflection of the cantilever according to

Hooke's law. Typically, the deflection is

measured using a laserspot reflected from

the top surface of the cantilever into an

array ofphotodiodes. Other methods thatare used include optical interferometry,

capacitive sensing or piezoresistive AFM

cantilevers.

http://en.wikipedia.org/wiki/Atomic_force_microscopy

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Near-Field Scanning Optical Microscopy (NSOM)

19

Methodology

Near-field scanning optical microscopy

(NSOM/SNOM) is a microscopy technique

for nanostructure investigation that breaks

the far field resolution limit by exploiting the

properties ofevanescent waves. This is

done by placing the detector very close

(distance much smaller than wavelength )

to the specimen surface. This allows forthe surface inspection with high spatial,

spectral and temporal resolving power. In

particular, lateral resolution of 20 nm and

vertical resolution of 25 nm have been

demonstrated.As in optical microscopy, thecontrast mechanism can be easily adapted

to study different properties, such as

refractive index, chemical structure and

local stress.http://en.wikipedia.org/wiki/Near-

field_scanning_optical_microscopy

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Focused Ion Beam Microscopy (FIB)

20

Methodology

http://en.wikipedia.org/wiki/Focused_ion_beam

Focused ion beam (FIB) systems operate in a similar fashion to a scanning

electron microscope (SEM) except, rather than a beam of electrons and as thename implies, FIB systems use a finely focused beam of ions (usually gallium)

that can be operated at low beam currents for imaging or high beam currents for

site specific sputtering or milling.

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Fabrication of Nanoscale Structures (1/3)

21

Methodology

Background

Fabricating structures at the nano level can be broken down into two main

methods; top down and bottom up construction.

Top Down Fabrication

Top down fabrication can be likened to sculpting from a block of stone. A

piece of the base material is gradually eroded until the desired shape is

achieved. That is, you start at the top of the blank piece and work your way

down removing material from where it is not required. Nanotechnology

techniques for top down fabrication vary but can be split into mechanicaland chemical fabrication techniques.

Top Down Fabrication Techniques

The most top down fabrication technique is nanolithography. In this process,

required material is protected by a mask and the exposed material is etchedaway. Depending upon the level of resolution required for features in the

final product, etching of the base material can be done chemically using

acids or mechanically using ultraviolet light, x-rays or electron beams. This

is the technique applied to the manufacture of computer chips.

http://people.bath.ac.uk/acb40/Dreamweaver%20Website/nanometrologyandnanomanufacturing.html

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22

Methodology

Bottom Up Fabrication

Bottom up fabrication can be likened to building a brick house. Instead of placingbricks one at a time to produce a house, bottom up fabrication techniques place

atoms or molecules one at a time to build the desired nanostructure. Such

processes are time consuming and so self assembly techniques are employed

where the atoms arrange themselves as required.

Bottom Up Fabrication Techniques

Self assembling nanomachines are regularly mentioned by science fiction writers

but significant obstacles including the laws of physics will need to be overcome or

circumvented before this becomes a reality. Other areas involving bottom up

fabrication are already quite successful. Manufacturing quantum dots by self-assembly quantum dots has rendered the top down lithographic approach to

semiconductor quantum dot fabrication virtually obsolete.

http://www.azonano.com/article.aspx?ArticleID=1835

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23

Methodology

http://www.azonano.com/article.aspx?ArticleID=1835

Top-down Bottom-up

Advantages

Once Research and Development

complete and manufacturing line is

complete costs drop

Bulk production

Self-Assembly processes

Less product defects

Disadvantages

Contamination

Machine Cost

Complexity

Clean room cost and complexity

Physical limits

Material damageSurface imperfections

Heat dissipation

Not very robust products

Lengthy process to obtain nanoparticles

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Outline

History

Definition

Methodology


Outline

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Chocolate

25

Applications

Crystal Melting temp. Notes

I 17 C (63 F) Soft, crumbly, melts too easily

II 21 C (70 F) Soft, crumbly, melts too easily

III 26 C (79 F) Firm, poor snap, melts too easily

IV 28 C (82 F) Firm, good snap, melts too easily

V 34 C (93 F) Glossy, firm, best snap, melts near body temperature (37 C)

VI 36 C (97 F) Hard, takes weeks to form

Self-assemblyMaking chocolate considered "good" is about forming as many type V crystals

as possible. This provides the best appearance and texture and creates themost stable crystals, so the texture and appearance will not degrade over time.

To accomplish this, the temperature is carefully manipulated during the

crystallization.

http://en.wikipedia.org/wiki/Chocolate

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Smart phone

26

Applications

http://en.wikipedia.org/wiki/IPhone

A smartphone is a mobile phone built on a mobile computing platform, with

more advanced computing ability and connectivity than a feature phone.The first

smartphones mainly combined the functions of a personal digital assistant (PDA)

and a mobile phone orcamera phone. Today's models also serve to combinethe functions ofportable media players, low-end compact digital cameras,

pocket video cameras, and GPS navigation units.

Modern smartphones typically also include high-resolution touchscreens, web

browsers that can access and properly display standard web pages rather than

just mobile-optimized sites, and high-speed data access via Wi-Fi and mobilebroadband.

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Cosmetics

27

Applications

In cosmetics there are currently two main uses for nanotechnology. The first of

these is the use of nanoparticles as UV filters. Titanium dioxide (TiO2) and

Zinc oxide (ZnO) are the main compounds used in these applications. Organic

alternatives to these have also been developed.

The second use is nanotechnology for delivery. Liposomes and niosomes are

used in the cosmetic industry as delivery vehicles. Newer structures such as

solid l ipid nanoparticles (SLN) and nanostructured lipid carriers (NLC)

have been found to be better performers than liposomes. In particular, NLCs

have been identified as a potential next generation cosmetic delivery agent that

can provide enhanced skin hydration, bioavailabili ty, stabil ity of the agent

and controlled occlusion. Encapsulation techniques have been proposed for

carrying cosmetic actives.

http://www.observatorynano.eu/project/filesystem/files/Cosmetics%20report-

April%2009.pdf

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Morpho

28

Applications

http://en.wikipedia.org/wiki/Morpho

Many Morpho butterflies are colored in metallic, shimmering shades ofblue

and green. These colors are an example ofiridescence: the microscopic scales

covering the Morpho's wings reflect incident light repeatedly at successive

layers, leading to interference effects that depend on both wavelength and

angle of incidence/observance. Thus the colors produced vary with viewing

angle, however they are actually surprisingly uniform, perhaps due to the

tetrahedral (diamond-like) structural arrangement of the scales or diffractionfrom overlying cell layers. This structure may be likened to a photonic crystal.

The lamellate structure of their wing scales has been studied as a model in the

development offabrics, dye-free paints, and anti-counterfeit

technology used in currency.

http://emily-louise-smith-chelsea.blogspot.tw/2010/12/morphotex.html

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Carbon Nanotube (CNTs)

Applications

High tensile strength (~63 GPa) >> High-carbon steel (1.2 GPa)High elastic modulus (~ 1 TPa)

High thermal conductivity along the nanotube (6000 W/m/K) >> Copper (385 W/m/K)

High electrical current density for armchair nanotubes (~1000 times that of metals)

http://en.wikipedia.org/wiki/Carbon_nanotube

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Multifunctional Nanowire Bioscaffolds

Chem. Mater. 2007, 19, 4454-4459.

A simple and inexpensive way tocreate a nanowire coating on the

surface of biocompatible titanium

has been developed. The technique

could be used to create more

effective surfaces for prosthetics,such as hip replacements, as well

as in dental reconstruction and

vascular stents. The material can

also be easily sterilised using

ultraviolet light and water or ethanol,

which means it could safely be

used in hospitals.

Accplications

A li ti

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Moores Law

"..(T)he first

microprocessor only had

22 hundred transistors.

We are looking at

something a million timesthat complex in the next

generationsa billion

transistors. What that

gives us in the way of

flexibility to designproducts is phenomenal."

Gordon E. Moore ,1965.

The number of transistors per square inch on integrated circuits double every year.

http://www.intel.com/technology/mooreslaw/index.htm

Applications

A li ti

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Lotus Effect

Applications

The lotus effect refers to the very high water repellence (superhydrophobicity)

exhibited by the leaves of the lotus flower (Nelumbo). Dirt particles are picked

up by water droplets due to a complex micro- and nanoscopic architecture of

the surface, which minimizes adhesion.

http://en.wikipedia.org/wiki/Lotus_effect

The hydrophobicity of a surface is

related to its contact angle. The

higher the contact angle the higher

the hydrophobicity of a surface.

Surfaces with a contact angle < 90

are referred to as hydrophilic and

those with an angle >90 as

hydrophobic. Plants with a double

structured surface like the lotus can

reach a contact angle of 170

whereas a droplets actual contact

area is only 0.6%. All this leads to a

self-cleaning effect.

Applications

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Fuel Cells

Applications

http://www.understandingnano.com/fuel-cells.html

Catalysts are used with fuels such as hydrogen or methanol to produce

hydrogen ions. Platinum, which is very expensive, is the catalyst typically usedin this process. Companies are using nanoparticles of platinum to reduce the

amount of platinum needed, or using nanoparticles of other materials to

replace platinum entirely and thereby lower costs.

Fuel cells contain membranes that allow hydrogen ions to pass through thecell but do not allow other atoms or ions, such as oxygen, to pass through.

Companies are using nanotechnology to create more efficient membranes;

this will allow them to build lighter weight and longer lasting fuel cells.

Researchers at Rensselaer Polytechnic Institute have investigated the storageof hydrogen in graphene (single atom thick carbon sheets). Hydrogen has a

high bonding energy to carbon, and the researchers used annealing and

plasma treatment to increase this bonding energy.

Outline

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Outline

History

Definition Methodology


Outline

Challenges Risks and Ethics

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Challenges, Risks, and Ethics

Challenges, Risks, and Ethics

1. Monitoring the exposure of nanoscale engineered to humans in the

air and within water. The challenge becomes increasingly difficult in

more complex matrices like food.

2. Developing and validating methods to evaluate the toxicity of

engineered nano-materials.

3. Constructing models for predicting the potential impact ofengineered nano-materials on the environment and human health.

4. Educating people about the pros and cons for nanotechnology.

5. Defining areas applicable to nanotechnology with regulations and

laws. Overemphasized functions of nanotechnology should be

prohibited.

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