Plasma-enhanced chemical vapor deposition (PECVD) is a well-known method for the synthesis of carbon nanotube (CNT) forests with the electric field in the plasma sheath being responsible for the vertical orientation of CNTs. Here, we investigate the deformation mechanism and mechanical properties of pristine and conformally coated PECVD CNT forests under compressive loading. Our in situ indentation experiments reveal that local buckles form along the height of pristine CNTs progressing downward from the starting point at the tips. For CNT forests coated from their roots to top with alumina using atomic layer deposition (ALD), the deformation mechanism depends strongly on the coating thickness. The buckling behavior does not change significantly when the coating is 5-nm thick. However, with a 10-nm-thick coating, the nanotubes fracture—that is, at both the CNT core and alumina coating. Ex situ indentation experiments with a flat punch reveal 8- and 22-fold increase in stiffness with the 5- and 10-nm coating, respectively. Comparing the behavior of the PECVD forests with CNTs grown with thermal chemical vapor deposition (CVD) shows that the mechanical behavior of PECVD CNTs depends on their characteristic morphology caused by the growth parameters including plasma. Our findings could serve as guidelines for tailoring the properties of CNT structures for various applications in which CNT compliance or deformation plays a critical role.

References

References
1.
Cola
,
B. A.
,
Xu
,
J.
, and
Fisher
,
T. S.
,
2009
, “
Contact Mechanics and Thermal Conductance of Carbon Nanotube Array Interfaces
,”
Int. J. Heat Mass Transfer
,
52
(
15–16
), pp.
3490
3503
.
2.
Nguyen
,
J. J.
,
Bougher
,
T. L.
,
Abadi
,
P. P. S. S.
,
Sharma
,
A.
,
Graham
,
S.
, and
Cola
,
B. A.
,
2013
, “
Postgrowth Microwave Treatment to Align Carbon Nanotubes
,”
ASME J. Micro Nano-Manuf.
,
1
(
1
), p.
014501
.
3.
Lin
,
W.
,
Shang
,
J. T.
,
Gu
,
W. T.
, and
Wong
,
C. P.
,
2012
, “
Parametric Study of Intrinsic Thermal Transport in Vertically Aligned Multi-Walled Carbon Nanotubes Using a Laser Flash Technique
,”
Carbon
,
50
(
4
), pp.
1591
1603
.
4.
Pathak
,
S.
,
Lim
,
E. J.
,
Abadi
,
P. P. S. S.
,
Graham
,
S.
,
Cola
,
B. A.
, and
Greer
,
J. R.
,
2012
, “
Higher Recovery and Better Energy Dissipation at Faster Strain Rates in Carbon Nanotube Bundles: An In-Situ Study
,”
ACS Nano
,
6
(
3
), pp.
2189
2197
.
5.
Maschmann
,
M. R.
,
Dickinson
,
B.
,
Ehlert
,
G. J.
, and
Baur
,
J. W.
,
2012
, “
Force Sensitive Carbon Nanotube Arrays for Biologically Inspired Airflow Sensing
,”
Smart Mater. Struct.
,
21
(
9
), p.
094024
.
6.
Ehlert
,
G. J.
,
Maschmann
,
M. R.
, and
Baur
,
J. W.
,
2011
, “
Electromechanical Behavior of Aligned Carbon Nanotube Arrays for Bio-Inspired Fluid Flow Sensors
,”
Proc. SPIE
7977
, p. 79771C.
7.
Abadi
,
P. P. S. S.
,
Hutchens
,
S. B.
,
Greer
,
J. R.
,
Cola
,
B. A.
, and
Graham
,
S.
,
2012
, “
Effects of Morphology on the Micro-Compression Response of Carbon Nanotube Forests
,”
Nanoscale
,
4
(
11
), p.
8
.
8.
Pathak
,
S.
,
Mohan
,
N.
,
Decolvenaere
,
E.
,
Needleman
,
A.
,
Bedewy
,
M.
,
Hart
,
A. J.
, and
Greer
,
J. R.
,
2013
, “
Local Relative Density Modulates Failure and Strength in Vertically Aligned Carbon Nanotubes
,”
ACS Nano
,
7
(
10
), pp.
8593
8604
.
9.
Cao
,
A. Y.
,
Dickrell
,
P. L.
,
Sawyer
,
W. G.
,
Ghasemi-Nejhad
,
M. N.
, and
Ajayan
,
P. M.
,
2005
, “
Super-Compressible Foamlike Carbon Nanotube Films
,”
Science
,
310
(
5752
), pp.
1307
1310
.
10.
Maschmann
,
M. R.
,
Zhang
,
Q.
,
Wheeler
,
R.
,
Du
,
F.
,
Dai
,
L.
, and
Baur
,
J.
,
2011
, “
In Situ SEM Observation of Column-Like and Foam-Like CNT Array Nanoindentation
,”
ACS Appl. Mater. Interfaces
,
3
(
3
), pp.
648
653
.
11.
Maschmann
,
M. R.
,
Zhang
,
Q. H.
,
Du
,
F.
,
Dai
,
L. M.
, and
Baur
,
J.
,
2011
, “
Length Dependent Foam-Like Mechanical Response of Axially Indented Vertically Oriented Carbon Nanotube Arrays
,”
Carbon
,
49
(
2
), pp.
386
397
.
12.
Hutchens
,
S. B.
,
Hall
,
L. J.
, and
Greer
,
J. R.
,
2010
, “
In Situ Mechanical Testing Reveals Periodic Buckle Nucleation and Propagation in Carbon Nanotube Bundles
,”
Adv. Funct. Mater.
,
20
(
14
), pp.
2338
2346
.
13.
Lu
,
Y. C.
,
Joseph
,
J.
,
Maschmann
,
M. R.
,
Dai
,
L.
, and
Baur
,
J.
,
2013
, “
Rate-Dependent, Large-Displacement Deformation of Vertically Aligned Carbon Nanotube Arrays
,”
Challenges in Mechanics of Time-Dependent Materials and Processes in Conventional and Multifunctional Materials
, Vol.
2
,
B.
Antoun
,
H. J.
Qi
,
R.
Hall
,
G. P.
Tandon
,
H.
Lu
, and
C.
Lu
, eds.,
Springer
,
New York
, pp.
101
107
.
14.
Qiu
,
A.
,
Bahr
,
D. F.
,
Zbib
,
A. A.
,
Bellou
,
A.
,
Mesarovic
,
S. D.
,
McClain
,
D.
,
Hudson
,
W.
,
Jiao
,
J.
,
Kiener
,
D.
, and
Cordill
,
M. J.
,
2011
, “
Local and Non-Local Behavior and Coordinated Buckling of CNT Turfs
,”
Carbon
,
49
(
4
), pp.
1430
1438
.
15.
Maschmann
,
M. R.
,
Ehlert
,
G. J.
,
Park
,
S. J.
,
Mollenhauer
,
D.
,
Maruyama
,
B.
,
Hart
,
A. J.
, and
Baur
,
J. W.
,
2012
, “
Visualizing Strain Evolution and Coordinated Buckling Within CNT Arrays by In Situ Digital Image Correlation
,”
Adv. Funct. Mater.
,
22
(
22
), pp.
4686
4695
.
16.
Zbib
,
A.
,
Mesarovic
,
S. D.
,
Lilleodden
,
E.
,
McClain
,
D.
,
Jiao
,
J.
, and
Bahr
,
D.
,
2008
, “
The Coordinated Buckling of Carbon Nanotube Turfs Under Uniform Compression
,”
Nanotechnology
,
19
(
17
), p.
175704
.
17.
Mesarovic
,
S. D.
,
McCarter
,
C. M.
,
Bahr
,
D. F.
,
Radhakrishnan
,
H.
,
Richards
,
R. F.
,
Richards
,
C. D.
,
McClain
,
D.
, and
Jiao
,
J.
,
2007
, “
Mechanical Behavior of a Carbon Nanotube Turf
,”
Scr. Mater.
,
56
(
2
), pp.
157
160
.
18.
McCarter
,
C. M.
,
Richards
,
R. F.
,
Mesarovic
,
S. D.
,
Richards
,
C. D.
,
Bahr
,
D. F.
,
McClain
,
D.
, and
Jiao
,
J.
,
2006
, “
Mechanical Compliance of Photolithographically Defined Vertically Aligned Carbon Nanotube Turf
,”
J. Mater. Sci.
,
41
(
23
), pp.
7872
7878
.
19.
Qiu
,
A.
, and
Bahr
,
D. F.
,
2013
, “
The Role of Density in the Mechanical Response of CNT Turfs
,”
Carbon
,
55
, pp.
335
342
.
20.
Abadi
,
P. P. S. S.
,
Hutchens
,
S. B.
,
Greer
,
J. R.
,
Cola
,
B. A.
, and
Graham
,
S.
,
2013
, “
Buckling-Driven Delamination of Carbon Nanotube Forests
,”
Appl. Phys. Lett.
,
102
(
22
), p.
223103
.
21.
Abadi
,
P. P. S. S.
,
Maschmann
,
M. R.
,
Baur
,
J. W.
,
Graham
,
S.
, and
Cola
,
B. A.
,
2013
, “
Deformation Response of Conformally Coated Carbon Nanotube Forests
,”
Nanotechnology
,
24
(
47
), p.
475707
.
22.
Abadi
,
P. P. S. S.
,
Maschmann
,
M. R.
,
Mortuza
,
S. M.
,
Banerjee
,
S.
,
Baur
,
J. W.
,
Graham
,
S.
, and
Cola
,
B. A.
,
2014
, “
Reversible Tailoring of Mechanical Properties of Carbon Nanotube Forests by Immersing in Solvents
,”
Carbon
,
69
, pp.
178
187
.
23.
Hofmann
,
S.
,
Ducati
,
C.
,
Robertson
,
J.
, and
Kleinsorge
,
B.
,
2003
, “
Low-Temperature Growth of Carbon Nanotubes by Plasma-Enhanced Chemical Vapor Deposition
,”
Appl. Phys. Lett.
,
83
(
1
), pp.
135
137
.
24.
Meyyappan
,
M.
,
Delzeit
,
L.
,
Cassell
,
A.
, and
Hash
,
D.
,
2003
, “
Carbon Nanotube Growth by PECVD: A Review
,”
Plasma Sources Sci. Technol.
,
12
(
2
), pp.
205
216
.
25.
Teo
,
K. B. K.
,
Hash
,
D. B.
,
Lacerda
,
R. G.
,
Rupesinghe
,
N. L.
,
Bell
,
M. S.
,
Dalal
,
S. H.
,
Bose
,
D.
,
Govindan
,
T. R.
,
Cruden
,
B. A.
,
Chhowalla
,
M.
,
Amaratunga
,
G. A. J.
,
Meyyappan
,
M.
, and
Milne
,
W. I.
,
2004
, “
The Significance of Plasma Heating in Carbon Nanotube and Nanofiber Growth
,”
Nano Lett.
,
4
(
5
), pp.
921
926
.
26.
Chhowalla
,
M.
,
Teo
,
K. B. K.
,
Ducati
,
C.
,
Rupesinghe
,
N. L.
,
Amaratunga
,
G. A. J.
,
Ferrari
,
A. C.
,
Roy
,
D.
,
Robertson
,
J.
, and
Milne
,
W. I.
,
2001
, “
Growth Process Conditions of Vertically Aligned Carbon Nanotubes Using Plasma Enhanced Chemical Vapor Deposition
,”
J. Appl. Phys.
,
90
(
10
), pp.
5308
5317
.
27.
Milne
,
W. I.
,
Teo
,
K. B. K.
,
Amaratunga
,
G. A. J.
,
Legagneux
,
P.
,
Gangloff
,
L.
,
Schnell
,
J. P.
,
Semet
,
V.
,
Binh
,
V. T.
, and
Groening
,
O.
,
2004
, “
Carbon Nanotubes as Field Emission Sources
,”
J. Mater. Chem.
,
14
(
6
), pp.
933
943
.
28.
Xu
,
J.
, and
Fisher
,
T. S.
,
2006
, “
Enhancement of Thermal Interface Materials With Carbon Nanotube Arrays
,”
Int. J. Heat Mass Transfer
,
49
(
9–10
), pp.
1658
1666
.
29.
Khanikar
,
V.
,
Mudawar
,
I.
, and
Fisher
,
T.
,
2009
, “
Effects of Carbon Nanotube Coating on Flow Boiling in a Micro-Channel
,”
Int. J. Heat Mass Transfer
,
52
(
15–16
), pp.
3805
3817
.
30.
Guillorn
,
M. A.
,
Melechko
,
A. V.
,
Merkulov
,
V. I.
,
Hensley
,
D. K.
,
Simpson
,
M. L.
, and
Lowndes
,
D. H.
,
2002
, “
Self-Aligned Gated Field Emission Devices Using Single Carbon Nanofiber Cathodes
,”
Appl. Phys. Lett.
,
81
(
19
), pp.
3660
3662
.
31.
Koehne
,
J.
,
Chen
,
H.
,
Li
,
J.
,
Cassell
,
A. M.
,
Ye
,
Q.
,
Ng
,
H. T.
,
Han
,
J.
, and
Meyyappan
,
M.
,
2003
, “
Ultrasensitive Label-Free DNA Analysis Using an Electronic Chip Based on Carbon Nanotube Nanoelectrode Arrays
,”
Nanotechnology
,
14
(
12
), p.
1239
.
32.
Flicker
,
J.
, and
Ready
,
W. J.
,
2014
, “
Texturing of Polycrystalline Photovoltaic Materials Using Vertically Aligned Carbon Nanotube Arrays
,”
Prog. Photovoltaics: Res. Appl.
,
22
(
6
), pp.
634
640
.
33.
Hamdan
,
A.
,
Cho
,
J.
,
Johnson
,
R.
,
Jiao
,
J.
,
Bahr
,
D.
,
Richards
,
R.
, and
Richards
,
C.
,
2010
, “
Evaluation of a Thermal Interface Material Fabricated Using Thermocompression Bonding of Carbon Nanotube Turf
,”
Nanotechnology
,
21
(
1
), p.
015702
.
34.
Cui
,
H.
,
Zhou
,
O.
, and
Stoner
,
B. R.
,
2000
, “
Deposition of Aligned Bamboo-Like Carbon Nanotubes Via Microwave Plasma Enhanced Chemical Vapor Deposition
,”
J. Appl. Phys.
,
88
(
10
), pp.
6072
6074
.
You do not currently have access to this content.