How Small Can You Get? A human hair is about 100 microns (micrometers) wide One micron is about 0.001 times the thickness of a dime Current microchip transistors are 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) Current applications inertial sensors (e.g., in air bags) medical devices memory and mass storage micro-mirrors for digital projection (DLP)

A “Nano” Guitar!

Population Densities 55 million transistors per chip 10 billion components / wafer 6 billion people / world

The Shrinking Transistor

How Can We See Small Things? Atomic Force Microscopy cadmium selenide silicon

Refrigerator Magnet Imaging sample pull probe strip probe pull probe strip

What is the best representation? (c)

Imaging Atoms Scanning-Tunneling Electron Microscopy (STEM) image shows individual platinum atoms (bright blobs) on an alumina support, with Pt3 clusters circled. STEM image of a silicon crystal in the [112] orientation reveals pairs of atom columns in which the intrapair separation is 0.78 Å.

Joseph Stroscio; Robert Celotta / NIST Manipulating Atoms A single cobalt atom Joseph Stroscio; Robert Celotta / NIST 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.

Forms of Carbon (Allotropes) diamond graphite “buckytube” “buckyball” ~0.70 nm

Single-walled nanotube (SWNT) Growing Nanotubes Forest of nanotubes Single-walled nanotube (SWNT)