Transcript Semiconducting Nanowires as Nanoelectronic Building Blocks

Semiconducting Nanowires as
Nanoelectronic 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.
Vds
Vds
Vgs
ZnO
Alumina
ZnO
Alumina
Alumina
The Process
1. Mechanically and Electrically
Polished Aluminum
Al
2. Anodization
Al
Anodization
The Process
3. Pore Opening
Al
4. Evaporation
Al
Ti
Au
The Process
5. Bonding
5. Bonding
Al
Ti
Au
Epoxy
6. Lift-off
Ti
Au
Epoxy
Glass
Glass
The Process
7. Barrier Opening and Exposure
Ti
Au
Epoxy
Glass
8. Electrodeposition
Ti
Au
Epoxy
Glass
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.
AFM Probe
I
Ti
Au
Epoxy
Glass
The Results Part 2
• I-V Curve of a purely
Zn nanowire.
AFM Probe
100
0
Current (nA)
-100
-200
Alumina
Alumina
Zn
-300
-400
-500
-600
-700
-10
-5
0
Voltage (V)
5
10
The Results Part 3
Red-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