Transcript Slide 1
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