Nanoscience15 lectures + 3 tutorials

Dr Pete Nellist (coordinator)13 lectures + 2 tutorials

4007 SS Physics

nellistp@tcd.ie

Prof Suzi Jarvis Biological nanomaterials1 lecture

Prof John Boland Mechanical properties1 lecture

Books:•Introduction to Nanotechnology, Poole and Owens (Wiley)•Quantum Mechanics, McMurry•Quantum Semiconductor Structures, Weisbuch and Vintner (AP)

Timetable (subject to change)Lectures are at:

Tuesdays 5 pm in the Schroedinger Lecture Theatre.

Wednesdays 4 pm in the SNIAM Physics Lecture Theatre.

Date Lecturer25 January No lecture

All tutorials will be in the Trinity term.

Nellist Lectures

• Combination of figures on Powerpoint and handwritten notes.– Copies of handwritten notes will not be provided, so keep notes

during the lectures.

• Powerpoint presentations can be found at:

http://www.tcd.ie/Physics/People/Pete.Nellist/

Why nanoscience?

• Nanoscience (nanotechnology) is usually defined as being based on structures 1-100nm in dimension.– Typical interatomic spacing ~0.2nm, so can consist of a few tens

to hundreds of millions of atoms.

• Feynman talk “There’s plenty of room at the bottom” (www.zyvex.com/nanotech/feynman.html).– He is mainly discussing minaturization– Also can exploit quantum effects.

Moore’s law

Gordon Moore

1929-

• Moore’s law: The number of transistors on a chip doubles every two years.– Transistor dimensions are now as small as 65 nm, so this is

nanotechnology rather than microtechnology.

Single atoms

• These are Fe atoms positioned on a Cu surface.– They were positioned

using a scanning tunnelling microscope (STM).

– Don Eigler at IBM.

Metal nanoparticles

2 nm2 nm

2 nm

Metal nanoparticles and single atoms

1 monolayer (single atom and raft)

A B C

D

C

D

0

2 monolayers

Au cryst.

a b c d

1.0 Å

1.4 Å

10 Å

Multiply twinned particles

• Often nanoparticles are multiply twinned.– This is done to minimise the surface energy.

Catalysts

At the nanoscale, physics and chemistry converge

The Lycurgus Cup

• The Lycurgus Cup is unusual in that the reflected light colour (green) is different to the colour of transmitted light (red).

• The reason is that the glass contains 70 nm diameter nanoparticles of gold.– Nanoparticles of gold can appear to have different colours depending on

their size.

Buckminsterfullerene

• A carbon-60 molecule.– C60 is also known as Buckminsterfullerene (buckyballs).

– Other similar molecules (such as C70) exist.

• When doped with alkali metals, the resulting structure can act as a superconductor.

Carbon nanotubes• Discovered by Sumio

Iijima in 1991.– S. Iijima, Nature 354

(1991) 56.

• They can be metallic or semiconducting.

• They are mechanically extremely strong.– Use for composites?

Inorganic nanowire ropes

• These are ropes about 10 nm in diameter.

• They are made from individual chain molecules of Mo6S4.5I4.5.– The individual chains can

be seen in the image.

• These ropes are thought to have metallic properties.

Quantum Dots

• Show zero-dimensional quantum effects.

• Many optical applications– quantum lasers– light emitting diodes– single electron transistors

Quantum wells

• Also optically important– For example infra-red detectors

• Can also have quantum wires

Biological Macromolecules

Five Bakers Dancing!

DNA

Dioxy Ribonucleic Acid

Is sometime made synthetically for use as a nanostructure.

Spintronics

Hard disk read/write head.