How Small Can You Get?How Small Can You Get?

A human hair is about 100microns (micrometers) wide

One micron is about 0.001times the thickness of a dime

Current microchip transistorsare about two microns wide

The wires that connect the transistors are less than a micron wide

If vacuum tubes were used in place of the transistors on a microchip the chip would be the size of a city block!

Micromachines (MEMS)Micromachines (MEMS)

Current applications inertial sensors (e.g., in air bags) medical devices memory and mass storage micro-mirrors for digital projection (DLP)

A “Nano” Guitar!A “Nano” Guitar!

Population DensitiesPopulation Densities

55 million transistors per chip10 billion components / wafer

6 billion people / world

The Shrinking TransistorThe Shrinking Transistor

1970 1980 1990 2000 2010103

104

105

106

107

108

8080

8086

286

386™

486™ DX

Pentium®

Pentium II

Pentium III Pentium 4

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mb

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f tr

ansi

sto

rs

year

0.01

0.10

1.00

10.00

smallest featu

re size (micro

ns)

How Can We See Small Things?How Can We See Small Things?

Atomic Force Microscopy

cadmium

selenidesilicon

Refrigerator Magnet ImagingRefrigerator Magnet Imaging

pull probe strip

pull probe strip

probe

sample

What is the best representation?What is the best representation?

(a) (b) (c)

Imaging AtomsImaging Atoms

STEM image of a silicon crystal in the [112] orientation reveals pairs of atom columns in which the intrapair separation is 0.78 Å.

Scanning-Tunneling Electron

Microscopy (STEM) image shows individual platinum atoms (bright blobs) on an alumina support, with Pt3 clusters circled.

Manipulating AtomsManipulating Atoms

A 40-nanometer-wide NIST logo made with cobalt atoms on a copper surface. The ripples in the background are made by electrons, which create a fluid-like layer at the copper surface. Each atom on the surface acts like a pebble dropped in a pond.

Joseph Stroscio; Robert Celotta / NIST

A single cobalt atom

Forms of Carbon (Allotropes)Forms of Carbon (Allotropes)

~0.70 nm

graphite

“buckyball” “buckytube”

diamond

Growing NanotubesGrowing Nanotubes

Forest of nanotubes

Single-wallednanotube (SWNT)