Nanoparticle Devices
S. A. Campbell, ECE
C. B. Carter, CEMS
H. Jacobs, ECE
J. Kakalios, Phys.
U. Kortshagen, ME
Institute of Technology
Applications of nanoparticles
Flash Memory
Vertical Transistors
Tiwari et al., Appl. Phys. Lett. 68, 1377, 1996.
Nishigushi and Oda, J. Appl. Phys. 88, 4186, 2000
.
Silicon LEDs
Quantum Phosphor
Silicon Laser
Rowher et al., Sandia Natl. Lab., 2003.
Canham, Nature 408, 411, 2000.
Park et al., Appl. Phys. Lett., 78, 2575, 2001.
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The Vision: Nanoparticle Transistors
¾ Vertical Schottky Barrier FET
ƒ Does not require doping
ƒ Can be built on any kind of
substrate
ƒ 3D integration
ƒ Scales easily to very small size
Source
Gate oxide
Gate
Drain
Schottky Barrier FET
¾ What is needed?
Single crystal, defect-free silicon nanoparticles
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Improved Solar Cells
¾Light-induced defect creation (Staebler-Wronski effect)
limits efficiency of solar cells.
¾New materials appear promising:
“nanostructured silicon”
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Systems
Devices
Campbell
microscale Characteriztion
nanoscale Characterization
Carter
Jacobs
Kakalios
Synthesis
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Kortshagen
Uwe Kortshagen
Silicon nanoparticles for electronic devices
Dept. of Mechanical Eng.
¾ Novel electronic devices
such as vertical transistors
¾ Solid-state lighting: silicon
quantum dots as
environmentally benign
material
¾ More efficient solar cells
with increased stability
~ 2-nm silicon crystallite
in amorphous silicon matrix
Institute of Technology
Uwe Kortshagen
¾ Nonthermal plasmas for
silicon nanocrystals
¾ Design plasma
properties for optimal
particle properties
silicon particles for
electronic devices
¾ nanoparticles with
~1 trap site / particle
¾ nonagglomerated silicon
nanocrystals with narrow
size distribution.
Institute of Technology
C. Barry Carter
Nanoparticles of Silicon
Dept. of Ch. E. & Materials Science
¾ Structure by high-resolution TEM
¾ Ceramics, semiconductors and metals
¾ Link to properties through
collaborations
¾ The new HRTEM
Shape of nanoparticles
Defects and surface reactions
TEM:
the essential
tool for
nanoparticle
research
Institute of Technology
C. Barry Carter
Crystal of Si in amorphous Si
Devices and True Nanoparticles
¾
¾
¾
¾
Link to Devices
Morphology and Perfection
Crystals in Amorphous Films
Phase transformations
Stacking fault in
a 2nm particle!
Students:
Chris Perrey &
Julia Deneen
Twin boundary in
a 1.5nm particle!
The new HRTEM
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Jim Kakalios
Opto-Electronic Properties of
Nanostructured Silicon Thin Films
School of Physics and Astronomy
¾ Thin Film PECVD Amorphous
Silicon (a-Si:H) Preferred for
TFT’s and Solar Cells
¾ Light-Induced Defect Creation
Major Liability
¾ Silicon Nanocrystals Embedded
Within Amorphous Silicon
(a/nc-Si:H) Resist LightInduced Degradation
Institute of Technology
Jim Kakalios
¾ TEM confirms
nanocrystals in
a/nc-Si:H films
¾ Optical and Electrical
Properties of
Nanostructured
Material Comparable
to Best Quality a-Si:H
¾ Light-Induced Decay of
Photosensitivity (Ratio of
Photo-to-Dark
Conductivity) Reduced
in a/nc-Si:H Films
Institute of Technology
Steve Campbell
Nanoparticle Devices
Electrical and Computer Engineering
¾ Limits to the scaling of
planar CMOS in sight
¾ Possible new directions:
ƒ 3D integrated circuits
ƒ Mixing electronics/optics
/magnetics/etc. on the
same chip
¾ Single crystal
nanoparticles can be
used for both purposes
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Steve Campbell
Metal
¾ Methods for making
single crystal
semiconductor
nanoparticles
¾ Building and
characterizing
nanoparticle devices
ƒ MSM structures
ƒ Silicon transistors
Metal
Silicon Nanoparticle
Source
Gate oxide
Gate
Drain
Schottky Barrier FET
¾ NP properties highly
dependent on surface
¾ Good interfaces possible
¾ Outstanding performance
expected due to low C
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Heiko O. Jacobs
Self-Assembly of Nanoparticle Building Blocks
Electrical and Computer Engineering Dept.
¾ Electrostatic interaction can be
used to position 5 nm - 50 μm
sized components
¾ Sub-100 nm resolution has been
accomplished
¾ Programmability will be
possible using programmable
electrodes/receptors
charged area
RIGID SUPPORT
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Heiko O. Jacobs
¾ Parallel charge patterning
by Electric Nanocontact
Lithography
¾ Electrostatically driven
self-assembly of
nanoparticles from the
liquid and gas phases
SWNT Rope bundle
¾ Developed a technique to
pattern charge with 100 nm
resolution
¾ Developed a nanoxerographic
printer to print nanoparticles
with ~60 nm resolution
Institute of Technology