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