Small diamonds: what are they good for?

Dr James RabeauDepartment of PhysicsMacquarie University

Sydney, Australia

5 mm

5 mm5 cm

50 nm

(10-2) (10-3) (10-6)

(10-9)

April 28, 2010

A little bit about scale

1metre = 1 metre1centimetre = 1/100 metre1millimetre = 1/1000 metre1 micrometre = 1/1000000 metre1 nanometre = 1/1000000000 metre

Human hair = 50 micrometresNanodiamond = 1-50 nanometres (about 1000 times smaller than hair)

The biggest big-wig in Australia talks about them!!

We can make diamonds!

Gaseous Reagents

Surface Processes

Bulk Processesand Properties

REACTANTS

SUBSTRATE

H2 + CH4

Gaseous Processes

ACTIVATION

e-, heatH2 2H

CH4 + H CH3 + H2

FLOW AND REACTION

Diffusion

15 torr H2

0.1 to 1 % CH4

800 C, 800 Watts

Chemical vapour deposition (CVD) of diamond

Jim Butler

CVD system used for these experiments (glorified microwave oven)

Controls

ChamberMagnetron

Sample loading

Typical conditions:

1.2 kW40 Torr500 sccm0.7% CH4 / H2

800 C

Microwave CVD of polycrystalline diamond

Isolated diamond crystals

Nucleation Growth

H2/CH4

Continuous diamond film

Abrade with diamond powder (<0.25 µm)(combined with other materials…?)

50 nm diamondsµm diamonds

+N, B, He …

University of Bristol

Selective area deposition:- Patterned nucleationor-laser ablation, or other etching offilm after deposition.

Patterned diamond films

High-Pressure High-Temperature

CVD Single Crystal diamond

Apollo Rose – 4 mm Sumitomo8 mm

NRLCarnegie

(5 ct cut from 10ct)Univ. of Paris

Courtesy of Jim Butler

Nanodiamond powder

TEM

Other diamond comes in dust or powder form.Used for polishing, cutting tools etc.

Why does it matter?

Microscopy – seeing small things

What colour is sand?

What about the human body?

Sand grains are pretty big, what if we want to see smaller?

Anything smaller than around 1/2 micron cannot be resolved optically! That means the “grains” of sand would be invisible!

We need different techniques to see them.

http://learn.genetics.utah.edu/content/begin/cells/scale/

Think of these as nano-light globes

If we shine light (laser light) on them, they glow brightly!

Bio-Applications – Bio labelling, imaging and tracking Nanodiamond can be attached

to biological objects They are “biocompatible” They don’t “bleach”

Fu et al. PNAS 104 (2007)

Chang et al. Nature Nanotech 3 (2008)

Microscopy

So, by attaching nanodiamonds to biological objects, we can SEE more!

We can watch the bright nanodiamonds moving around, and what they do under certain circumstances

Ultimately, we can learn more about the human body, disease, and potential cures.

Diamonds in cells

Thank you for your attention, and I hope to see you in my physics lectures in a few years!

www.physics.mq.edu.au/research/qmapp