2. History of Nanoscience

Intro/history of nanoscience/tech

History and Future of Nanoscience / nanotechnology

Some history: Feynmans prophesy:

Theres plenty of room at the bottom What is nanoscience/nanotechnology? Nano-fabrication Nano tools Materials of nanoscience

Current applications of nano Future applications (dreams)


Feynmans Challenge (~1960)

Why cant we write the Encyclopedia Brittanica on the head of a pin?

Or the entire contents of the library of congress in the volume of a sugar cube?

There is plenty of room at the bottom.


Scales of lengthImportance of size and scale

1 m human being

Sun

10 m

1,000,000,000 m

0.001 m = milli

0.000000001 m = nano

0.000001 m = micro

1,000,000 m Earth

building

thickness of a dime

bacteria

atom

=109

=101

=106

=10-9

=10-6

=10-3

nanoscale


Nano is the scale of atoms and moleculesup to ...

The nanoscale ranges from individual atoms to bacteria.

1 nanometer = 10 atoms

1000 nanometers = 1 bacterium


The push to make things smaller


The power of miniaturization


Moores law


Top down fabrication (integrated circuits)

Use a microscope (light or electron) to write a pattern in a light sensitive layer.


Use an electron microscope beam to make very small patterns


Fabrication of semiconductor crystals -one atomic layer at a time

Produces atomically flat and perfect crystals - layer by layer Can be used for semiconductors or metals Molecular beam epitaxy - developed since ~1975


Fabrication of truly new materials

Molecular beam epitaxy is used to make new types of materials semiconductor devices (transistors,

computer circuits) lasers on a chip (fiber optics, optical

communications) very small and very sensitive read heads

for computer hard disks (laptops, ipods)


Rotary motor

Uses electrostatic force


A nano-mechanical oscillator

Fabrication


Nano-gravimiters


Fabrication from the bottom up

Nano is the scale of atoms -- need tools for visualizing and manipulating individual atoms.

Scanning probe microscopes (~1980s) Move a very small probe over a surface and

study the probe/surface interaction. Different types: Scanning tunneling microscope (STM) Atomic force microscope (AFM) Magnetic force microscope (MFM) + more


Scanning tunneling microscope (STM)

use tunneling currentfrom tip to sample

tunneling ~exp(-x) sohave very high xresolution (


Building - atom by atom

moving and placing Fe atoms on a Cu surface


Building with atoms

abacus with atoms quantum corral


Atomic force microscope (AFM)

move cantilever with atomically sharp tip over a surface or molecule

monitor deflection of cantilever (= spring with k=0.1 N/m -- like a slinky)

cantilever = 0.1 mm long can detect 10-11N and


Atomic force microscope tips

3000 nm

tips are only 10-100 atoms wide


AFM image of graphite surface

Individual atoms on a carbon surface.


DNA on a mica surface


Molecular Electronics

Use scanning probe microscopy to attach leads to individual molecules, and study electrical conduction.


Fabrication of a molecular switch

Conduction through a ROTAXANE molecule changes by a factor of 1000 when the active group is chemically oxidized. In a circuit the switch can be closed by application of a voltage.


New materials: carbon buckyballs and carbon nanotubes

Discovery of buckyballs (fullerenes) C60 and larger.

Can be used to pattern or trap at the nano-scale


Carbon nanotubes

Graphene sheets rolled into cylinders. As small as a few nm in diameter.

Very strong (space elevator?). Can conduct electricity. Use as small pipes, channels, or gears.


Fabrication by self assembly

Use natural properties of atoms and molecules to form nano-scale structures. Molecular beam epitaxy Carbon nanotubes DNA

Use as templates or in other ways.


Current applications of nanoscience

Very powerful computers, mp3 players, ipods Computer hard disks CDs and DVDs Nanostructured materials: ultra-strong and

ultra-light, used in tennis rackets, skiis, cars and airplanes


Nature is a nanoscientist

QuickTime and aGraphics decompressor

are needed to see this picture.

Nature uses nanoscalemolecular motors


Molecular motors walk from place to place within a cell

QuickTime and aVideo decompressor


QuickTime and aVideo decompressor


goal: make nanoscale motors following Natures design


Grand nanoscience challenges for the future

Putting the entire contents of the Library of Congress in a device the size of a sugar cube

Developing materials that are 10 times stronger than steel

Improving the speed and reducing the size of computers

Detecting cancerous tumors that are only a few cells in size (new sensor technologies)

Removing the finest contaminants from water and air

Making motors as small and efficient as biological motors (nano electro-mechanical systems)

Doubling the energy efficiency of solar cells


Nano threads

Tools scanning probe microscopy

Fabrication: top down vs bottom up self assembly

Materials silicon integrated circuits DNA carbon nanotubes and buckyballs

History and Future of Nanoscience / nanotechnologyFeynmans Challenge (~1960)Scales of lengthImportance of size and scaleNano is the scale of atoms and molecules up to ...The push to make things smallerThe power of miniaturizationMoores lawTop down fabrication (integrated circuits)Fabrication of semiconductor crystals -one atomic layer at a timeFabrication of truly new materialsRotary motorA nano-mechanical oscillatorNano-gravimitersFabrication from the bottom upScanning tunneling microscope (STM)Building - atom by atomBuilding with atomsAtomic force microscope (AFM)Atomic force microscope tipsAFM image of graphite surfaceDNA on a mica surfaceMolecular ElectronicsFabrication of a molecular switchNew materials: carbon buckyballs and carbon nanotubesCarbon nanotubesFabrication by self assemblyCurrent applications of nanoscienceNature is a nanoscientistMolecular motors walk from place to place within a cellGrand nanoscience challenges for the futureNano threads

Date post:	04-Mar-2016
Category:	Documents
Upload:	mihai-adriana-ionela
View:	19 times
Download:	0 times

2. History of Nanoscience

Documents