Biomedical Engineering Reference
In-Depth Information
Moreover, system miniaturization and device integration based
on reproducible fabrication processes and large scale production are
still the top prerequisites for low cost products. However, limitations
in the downscaling of the CNT-based sensors are foreseeable.
Therefore, new carbon-based functional nanomaterials — surface-
modified, properly manipulated, and engineered, with new properties
and functionalities at nanoscale will emerge to fill these important
sensor tasks in the miniaturized sensor systems for advanced gas
detection.
In Table 9.9, a nonexhaustive review of CNT-based chemical
sensors is proposed for different targeted analytes by means of
various transducers developed.
Table 9.9
Summary of CNT-based gas sensors using different transducers
Materials/
methods
Analyte
Transducer
Main performance
Ref.
NO
SWCNT
individual, mats
Chemiresistor
and FET
CR: 1-200 ppm
S:
[33]
2
~2 at 200 ppm
DL: 2 ppm; OT: RT;
Rst: <5 min
Rct: No reversibility at RT
R
/
R
f
i
NO
SWCNT network
by casting
Chemiresistor CR: 0-100 ppm
S: <5%/ppm
DL: 44 ppb; OT: RT;
Rst: <1 min
Rct: ~10 h (Rev. by
UV light)
[28]
2
NO
SWCNT network
by CVD
Chemiresistor CR: 20 ppm pulse; NH
[259]
2
3
pulse
S: NS
DL: NS; OT: RT;
Rst: <10 s
Rct: <15 min (Rev. UV
light)
NO
MWCNT film
by CVD
Chemiresistor CR: 10-100 ppb
S: 3
[262]
2
/10 ppb at 165°C
DL: <10 ppb NO
Ω
; OT:
2
165°C
Rst: <30 min
Rct: <2 h
NO
SWCNT film
by CVD
Chemiresistor CR: 50-1000 ppb
S:
[263]
2
~1.4 at 100 ppb
DL: 8 ppb; OT: RT
Rst: <1 min
Rct: <10 min
G
/
G
i
f