Transcript Fabrication and Testing of Nanoscale Devices Gurpreet Singh Assistant Professor, Mechanical and Nuclear Engineering Department, Kansas State University “http://www-personal.ksu.edu/~gurpreet/”

Fabrication and Testing of
Nanoscale Devices
Gurpreet Singh
Assistant Professor,
Mechanical and Nuclear Engineering Department,
Kansas State University
“http://www-personal.ksu.edu/~gurpreet/”
Overview
• Introduction
– CNT Mechanical Properties and Challenges
– Introduction to 3-D nano-manipulation
• Device Fabrication and Testing




SEM Based
FIB Based
SEM vs. FIB
Example: Fabrication and calibration of an individual MWCNT/sphere device
as a mechanical force sensor.

Additional Outcomes:
 Laser trapping in air.
• Current Research
 Micro-nano piezoresistive sensors and piezoelectric nanowires, VT
 Electromechanical Testing stage, CU-Boulder
 SiCN coatings for high power laser thermal detectors, NIST-Boulder
• Summary/Conclusion
2
Carbon Nanotubes
SWCNT
Graphene Sheet
MWCNT
Allotrope of Carbon
D (SWNT): Few nm
Do (MWNT): Up to hundreds of nm
Aspect Ratio ≈ 104
3
Mechanical Properties: CNTs
•Wong et.al. Science 1997
E = 1.28±0.59 TPa
•Tombler et. al. Nature 2000
E ≈1.2 TPa
•Falvo et.al. Nature 1997
Large local strains ≈16%
•Yu et. al. Science 2000. E ≈ 270 to 950 GPa. st = 1163GPa. ef ≈12% (max.)
Zhu et. al. PNAS 2005. sf≈ 15.84 GPa at ef = 1.56%
“Primary focus is to include CNTs into engineered systems. And the potential to do4
this depends largely on the ability to manipulate them in 3-d space.”
The Scale
∆ 107 m
}
}
∆ 107 m
.
NT
Earth
Lamp
5
Nanoscale Manipulation Strategies
TEM
Real time
2- D
3- D
viewing Observation Manipulation
SEM
STM
AFM
0.1
3- D
Observation
2- D
Manipulation
1
10
100
1000
Scale of Objects (nm)
6
Some Nano-manipulation Tools
Quick foot
Nanotechnology 19, 49, 495503 2008
Nanotechnology, 17, 10, 2434 2006
Yu et al. Science 2000
7
SEM Based Nano-manipulation
Quick foot
B
C
A
Circular cover port
w/ feed through
8
SEM Based Nano-manipulation
(I)
B
(II)
Quick foot
C
A
(III)
(IV)
Circular cover port
w/ feed through
9
SEM Chamber: Manipulator installed
Electron Gun
Sample
Adapter Stage for
Manipulator
10
Device Fabrication: Pick-n-Place CNT
STEPS:
a. Install and align the manipulator in SEM.
b. Locate and separate individual CNT.
c. Welding the CNT on support structure needle tips.
(b)
(a)
(c)
11
G. Singh, P. Rice, R.L. Mahajan and J.R. McIntosh. Nanotechnology (2009).
Welding Inside the SEM
Acceleration Voltage
30 kV
Adsorbed HCs or
impurities
Primary Electron Beam
Oxygen molecule
Free or Amorphous
carbon
CO or CO2
P. E.
Pumped
out
volatile
Water vapors
S. E.
MWCNT
Resulting weld
P.E. = 30 kV; S.E. ≈ (0 – 50) eV
Dissociation of surface adsorbed impurity molecules (from the vacuum chamber) .
12
In-situ Mechanical Testing
(A) AFM Tip Alignment
AFM Tip
Chip (glued to the W Tip)
on which AFM Tip is
mounted
Tungsten Probe (mounted on
Nano-Manipulator Arm) 13
G. Singh, P. Rice, R.L. Mahajan and J.R. McIntosh. Nanotechnology (2009).
Tip Blunting
Rubbing against Zirconia Substrate
14
Mechanical Characterization
(B) Loading Test
Direction of application
of force
15
G. Singh, P. Rice, R.L. Mahajan and J.R. McIntosh. Nanotechnology (2009).
Mechanical Characterization
 (GPa)
Number
d (nm)
δmax. (nm)
A (mm2) (x10-3)
1
200±20
150±10
31±6.2
420±42
0.013 ±0.004
2
110±11
200±20
9.5±1.9
560±56
0.029±0.008
3
60±6
290±29
2.8±0.5
812±81.2
0.145±0.043
•
Fmax. (nominal) N (x10-9)
The device breaks at the welds while CNT survives the load test.
•
F max. ≈ 1 N
•
Maximum weld strength observed was ~ 0.14 GPa.
16
Device Fabrication: Pick-n-Place GaN NW
(a)
(b)
(c)
(d)
17
GaN Nanowire: APT Specimen Preparation
(a)
(b)
(c)
(d)
18
FIB Based 3-D nano-manipulation
FEI Helios 600 NanoLab Dual Beam at Virginia Tech and CU-Boulder
• FE-SEM & FIB: Ga LMIS
• 4 Gas Injector Systems
•Dual Beam
•Pt deposition (C9H16Pt)
•SiO2 deposition (TEOS)
•In-built Micromanipulator
•Insulator Enhanced Etch (XeF2)
•Gas Injectors •Selective Carbon Mill
•Big Chamber
• EBSD
• Cryo Chamber
• OmniprobeTM
19
Understanding the Geometry
Beams
Coincidence Point
52 °
4.1 mm
Image Source: internet
20
Understanding the Geometry
21
Eucentric height
Ctrl + i
Tungsten probe
Needle (~0.5 mm);
100 um above the surface
The value of Z at which tilt does not couple to
sample translation is called the "eucentric" height.
> Centering the feature
> Couple mag.
22
Locating a NT and Pt deposition
Making contact
Pt Deposition
Warm-up and insert Platinum deposition needle to avoid vibrations.
Lock the stage.
Fabricating devices using individual NTs
23
Separating a nanotube
EBEAM
Ion-BEAM
24
Fabricating devices using individual NTs
FIB: Machining and Fabrication
Si MEMS
25
CNT Device fabrication: SEM Vs. FIB
160
Electron Beam
Ion Beam
Estimated Time in min.
140
120
100
80
60
40
20
0
Sample
Mounting/Alignments
NT Location
NT Welding
Separation
FIB
Placement on test
structure
SEM w/ Nanomanipulator
26
Fabrication and Calibration of a CNT/sphere
Device as a Mechanical Force Sensor
Fabrication of CNT/Microsphere Device
(I)
(II)
I.R. Camera (side view)
(III)
(IV)
28
Final Device
Sphere d ≈ 4 m
Sphere d ≈ 10 m
29
Application as a Mechanical Force Sensor
• Mechanical force sensor for measuring forces
(nN). Study of deformation behavior of Tissues/
Single cells, e.g., Kinocilium in Ciliary Bundles
(sensory hairs).
• Calibration Tests against a pre-calibrated Si tip-less
cantilever (K = 0.0102 N/m).
• Calculation of Bending Modulus of individual
carbon nanotubes.
30
Applications in BioMechanics
Sensory hair bundle present in Utricle (inner ear)
Valentin Lulevich et al, Langmuir, 2006, 22 (19), 8151-8155•
Source: Prof. Wally Grant, Biomedical Eng., Virginia
Tech.
31
Alignment Inside SEM: Calibration Tests
Cantilever
Chip
K calibrated = 0.0102 N/m
Tip-less
Cantilever
Tungsten
Probe
32
Image Analysis: Superimposition
Application
of load
Red: zero load
Blue/Green: final step
33
G. Singh et. al. Nanotechnology 18 475501 (2007).
Force Vs Deflection : Calibration Tests
Force Vs Sphere Deflection
4.5E-08
4.0E-08
l Å 8 m
Force on Spher e (N)
3.5E-08
3.0E-08
l Å 10 m
2.5E-08
l Å 13  m
2.0E-08
1.5E-08
l Å 13.5  m
1.0E-08
l Å 15.5  m
l Å 14.5 m
5.0E-09
0.0E+00
0
2
4
6
8
10
12
Deflection of the Sphere (microns)
34
Bending Modulus of Individual CNT
• Linear Fit to Experimental Data
FT = Kn. dn
• For a Cantilever Beam Assumption:
Fn  (3Eb.I/Ln3). dn
Eb  KnLn3/3I
35
Bending Modulus: Results
Ln (m) (±0.5)
Kn(N/m)(10-3)
Eb in GPa
-
14.5
0.7±0.07
59±11.9
170.8
10
8
13.1±1.31
53±15.2
3
185.3
8
15.5
1.4±0.14
30±5.8
4
200*
-
13
3.2±0.32
30±6.3
5
200*
-
10
7.2±0.72
31±7.7
6
230.3
12
13.5
1.8±0.18
11±2.3
Nanotube
Do (nm)
1
125*
2
Di (nm)
36
Summary
• Fabricated a novel CNT/sphere device with varying CNT lengths
and sphere diameters.
• Performed in situ bending/calibration tests. Measured forces ranged
(10-8 to 10 -9)N. Important features are the range of forces and the
small size of the device.
• No deflection of the cantilever tip was observed for nanotube lengths
> 15 µm.
• Bending modulus of individual CNTs ranged (11- 59) GPa
depending on NT geometry.
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Laser Trapping in Air
NT Length> 15 m
Laser Trapping in Air
Specimen Plane
Objective
LASER
1064nm
Optical Trap
Highly focused
Fnet = F1+ F2
Laser
in
n sphere>n medium
Simple Schematic
39
Results: Laser Trapping
4 m polystyrene sphere on a ~25 m long CNT
SEM
1064 nm IR Laser at 100 mW, Spot size ~ 1 m.
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Results: Laser Trapping
11 m Polystyrene Sphere
SEM
Optical
1064 nm IR Laser at 100 mW, Spot size ~ 1 m.
No Appreciable sphere movement was observed in this case.
41
Current Research on Polymer
Derived SiCN
•Micro-nano piezoresistive sensors and piezoelectric nanowires, VT
•Electromechanical Testing stage, CU-Boulder
•SiCN coatings for high power laser thermal detectors, NIST-Boulder
42
Multifunctional Micro-Nanosensors
TYPE
La0.8Sr0.2MnO3
SiCN
CNTs
Gage factor
3-5
1000-4000
~800-3000
Stability
Good
Highly stable
Stable
Cost
Low
Expensive
Medium
Microsensor: SiCN-(La,Sr)MnO3 composites
(Automobile Applications)
(M. Karmarkar, G. Singh, S. Shah, R.L. Mahajan, and S. Priya. Large piezoresistivity phenomenon in SiCN
– (La,Sr)MnO3 composites. Applied Physics Letters (2009).)
Nanosensor: MWCNT+ SiCN (PDC): Coreshell geometry:
Pressure sensor for harsh environments
G. Singh, S. Priya, M. Hossu, S R Shah, S. Grover, Ali R Koymen and R L Mahajan. Synthesis, electrical
and magnetic characterization of core-shell carbon nanotube – SiCN nanowires. [Available online]: (2009).
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Multifunctional Micro-Nanosensors
Cross-linking and Pyrolysis of Organic Polymer (Silazanes):
700-1000C H2/NH3 are released;
leaving free ‘C’ behind
C Atoms: sp2 to C; sp3 to Si; not bonded to N.
Si Atoms: tetrahedrally to C and N. Nanodomains: 1-2 nm
44
Microsensor: SiCN-(La,Sr)MnO3 composites
Si Map
Mn Map
Load cell readout
sample
Resistancemultimeter
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Nano-sensor: Using Individual NWs
SiCN coated Carbon nanotubes: cross-linking and pyrolysis of PUMVS on the surfaces of CNTs
MWCNT
SiCN Coated
MWCNT
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G Singh et al. Materials Letters 2009
Electromechanical Tensile Testing
•
•
•
•
•
Microfabricated test stage for tensile measurements of nanofibers
Fixed and moving stages
Fixed stage is electrically isolated from moving stage
Thermal actuation
AC Impedance measurement circumvents specimen contact resistance
• Bending Beams as Springs, Lateral Stabilization, Heat Sinks, and Electrical
Connections for Specimen
Bending
Beams
Fixed Stage
Moving Stage
Thermal Actuator
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Collaboration: V. Bright Group: CU-Boulder
Electromechanical
Tensile Testing
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Collaboration: V. Bright Group: CU-Boulder
Tensile Testing: CNT
CNT
J.J. Brown, J.W. Suk, G. Singh, A.I. Baca, D.A. Dikin, R.S. Ruoff, and V.M. Bright.
Sensors and Actuators A: Physical [In Press] (2008).
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Nanocoatings for High Power Laser Thermal
Detectors
• NIST in Boulder maintains thermal detectors as measurement standards for
measuring optical power from laser sources (15000 W/cm2).
• Continue to seek a black coating (high damage threshold, high thermal
diffusivity and high optical absorbance) that can be easily applied and that
is durable like enamel paint, yet with the desirable properties of carbon
nanotubes (such as SiCN).
• Fundamental understanding of the effect of laser irradiation on carbonaceuos
nanomaterials.
G. Singh, P. Rice, K. Hurst, J. Lehman and R.L. Mahajan, Applied Physics Letters, 91, 033101 (2007).
Thermal Detector Coatings for IR Lasers
The coated surface is exposed
to lasers at 1.06 um and 10.6
um. These coatings showed no
damage even at >10 kW/cm2.
As Deposit
1.06 um
10. 6 um
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Final Summary
•
There is a continuous need for testing standards at the nanoscale.
•
Electron microscope based manipulation works well for pick, place and
fabrication of high aspect ratio nanowire based devices and larger size
specimen.
•
FIB can be used to section and deposit material at the nanoscale. FIB based
manipulation outperforms SEM based manipulation on many levels.
•
This work is important for fundamental understanding of the materials at
nano-scale. It can be extended to the design and development of many other
‘proof of principle’ devices.
•
Fabrication of a novel CNT/sphere device: Development of high precision
force sensor.
• Laser Trapping in Air.
Collaborative research on micro and nano composite materials (sensor),
nanocoatings (IR Lasers, UV Lasers).
•
52
Acknowledgements
•
Physics Department, Kansas State University.
•
Advisors and Mentors.
•
1.
2.
3.
4.
5.
6.
7.
Collaborators:
ICTAS, Virginia Tech., NIST and Oak Ridge National Lab.
Prof. Harry Dorn, Nichole Rylander, Tom Campbell, Rafael Davalos, S Priya
Cindi Schwartz, Mary Morphew, Mark Ladinsky (Nano-knife project).
Tasshi Dennis (Bio-Optics).
John Lehman, Katie Hurst, Darryl (Excimer Laser Cleaning).
Andrew Slifka and Damien (Optical Trapping).
Corrie Spoon, Prof. Wally Grant (Engineering Science and Mechanics, VT).
•
M.E. Faculty members and students.
53
THANK YOU!!
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