Science and Technology of Nanostructures

Physics 805, Fall 2009 F. J. Himpsel Syllabus, Info, Lecture Notes :

http://uw.physics.wisc.edu/~himpsel/Nano/lectures.htm

Nanotechnology in our Daily Life Iridescent car paint: Based on interference colors (like a butterfly, no bleaching after 5 years Miami)

Well 6 nm Nanotechnology on our Desktops Source Transistor Gate Drain Gate oxide 4 nm Hard Disk Sensor Medium Switching layer 5 nm Magnetic grain 10 nm

Quantum Well Laser: Designing the Perfect Trap 6 nm : Optimum Thickness

Nanocrystals Quantum effect: Crystal size determines the color (blue-shifted when smaller)

When does silicon cease to be silicon?

The band gap of silicon nanoclusters 3 nm : Gap begins to change GaAs Bulk Silicon

Transistor Gate Oxide Power consumption by a leaky gate oxide: A show-stopper for silicon technology?

Hard Disk Reading Head 5 nm Optimum

How small is a Nanometer ?

Each panel 10x smaller Each time something different Hewlett-Packard molecular memory

125 nm

Two more steps to reach one nanometer

10 27 Universe

(largest length)

10 –3 m

m

10 –6

 m

10 –9 n

m The Sun is a billion times larger than a human, and a nanometer is a billion times smaller.

10 –35 Planck Length

(smallest length)

The Physicist’s View: Fundamental Length Scales

Consider devices operating at room temperature. Their energy levels have to be separated by more than the thermal energy k B T = 25 meV .

Convert this energy scale to a length scale by fundamental constants.

Quantum Quantum Well: Quantum Well Laser Electric Capacitor: Single Electron Transistor Magnetic Magnetic Particle: Data Storage Media E 1 E 0

l

Energy Levels 3h 2 /8m

l

2

l

< 7

nm

d

Charging Energy 2e 2 / 

d d

< 9

nm

a

=

V

1/3 Spin Flip Barrier ½ M 2

a

3

a

> 3

nm

3.4 nm pitch 10 base pairs Biological Length Scales in the Nanometer Range DNA Virus (TMV) 300 nm 2 nm 11 nm 18 nm

This end is attached to another muscle fiber, pulling it along .

Walker = myosin, kinesin

Molecular Motor

Driven by the reaction ATP  ADP + Energy Linear Motor (Muscle) Vale and Milligan, Science 288, 88 (2000) Rail = actin, tubulin = part of a muscle fiber

Life-like Structures at a Surface

Wieczorek et al., Website Electrolyte Artificial Membrane Water Solid substrate Bacteriorhodopsin as light-driven proton pump Rotary generator = Rotary motor in reverse Converts ADP to ATP Powered by proton pump Cornell et al., Nature

387

, 580 (1997); Tanaka & Sackmann, Phys. Stat. Sol. A

203

, 3452 (2006).

Knitting with Polymers

In Pursuit of the Ultimate Storage Medium : 1 Bit = 1 Atom Silicon Surface CD-ROM 1.6 nm Track 10  m 10 n m Density x 1 000 000

Speed versus Density Shot noise speed limit

DNA

Density limit: 5x4 cell = 20 atoms/bit • Speed is sacrificed as density increases (less signal per bit) • Density is limited by coupling between bits (range ~4 atoms)

When will we be down to atoms ?

Using Moore's Law ...

250 Terabit/inch 2 Year 2038

Nanotechnology: A Moving Target

nano nano + bio nano + bio + info Lithography Self-assembly Directed Assembly

The Madison Discovery Institutes (Nano + Bio + Info)

"Disruptive Technologies" A business model for Nanotechnology ?

Start with niche applications, then break into mass markets.

Clayton Christensen Harvard Business School