semiconducting nanowires as nanoelectronic building blocks evan brown professor grace lu group...

Semiconducting Nanowires as Semiconducting Nanowires as Nanoelectronic Building BlocksNanoelectronic Building Blocks

Evan Brown

Professor Grace Lu Group

September 2nd, 2005

The Goal

• To make Zn nanowires using electrodeposition.

• To convert those wires into ZnO wires via thermal oxidization.

• To characterize the wires.

The Goal Part 2

• Nanowires vertically aligned in a highly ordered template.

• Future small scale transistors.

• Can be used as the building blocks for simple logic gates and memory elements.

VdsVds Vgs

ZnO ZnO

Alumina Alumina Alumina

The Process

2. Anodization

Al

1. Mechanically and ElectricallyPolished Aluminum

Al

Anodization

The Process3. Pore Opening

Al

4. Evaporation

Ti

Au

Al

The Process

5. Bonding

Ti

Au

Al

Epoxy

Glass

5. Bonding

Ti

AuEpoxy

Glass

6. Lift-off

The Process

Ti

AuEpoxy

Glass

7. Barrier Opening and Exposure

Ti

AuEpoxy

Glass

8. Electrodeposition

Electrodeposition

• Originally, DC biasing was used to deposit.

• This gave varying results.

Electrodeposition Part 2

• With different parameters came different results, but still not ideal.

Electrodeposition Part 3

Electrodeposition Part 4• We then tried Pulsed

Electrodeposition (PED) to improve the filling factor and uniformity of growth.

• An initial filling factor of ~75% was achieved.

Electrodeposition Part 5

• Again,

vs.

PED/DC

• Diffusion is the key.

• DC electrodeposition does not allow the electrolyte to diffuse evenly throughout all the pores.

• PED can be tailored to allow for the electrolyte's natural diffusion.

The Results

• Preliminary electrical transport measurements have been taken.

Ti

AuEpoxy

Glass

AFM Probe

I

The Results Part 2• I-V Curve of a purely

Zn nanowire.

Alumina

Zn

Alumina

AFM Probe

-10 -5 0 5 10-700

-600

-500

-400

-300

-200

-100

0

100

Cu

rre

nt

(nA

)

Voltage (V)

The Results Part 3Red-Ti

Blue-Zn

The Results Part 4

Red-Ti

Blue-Zn

Green-ZnO

Acknowledgements

• Professor Jia “Grace” Lu, Joseph Fan, Dawei Wang, Marco Huang, CJ Chien.

• Said Shokair and the IM-SURE program.

• National Science Foundation