Single-walled carbon nanotubes based chemicapacitive sensors.
Carboxylated single-walled carbon nanotubes (SWNTs) based chemicapacitive gas sensors were fabricated by AC dielectrophoretically aligning SWNTs across microfabricated gold electrodes with controlled density/device resistance. Two different sensing configurations (i.e., horizontal/in-plane and vertical/out-of-plane) were utilized to compare their sensing performance. Upon exposure to water vapor at room temperature, the response (R = [(C--C0)/C0] x 100%) increased with an increase in water vapor concentration similar to that of resistance response. In horizontal configuration, the response was increased with an increase in device resistance which might be attributed to preferentially alignment of semiconducting SWNTs during initial phase of alignment. However, the response was independent of device resistance in vertical/out-of-plane configuration which indicated that the sensing mechanism is based on the change of dielectric constant of gate and atmosphere.
Materials Processing Division, Korea Institute of Materials Science, 66, Sangnam-dong, Changwon, 641-010, Korea.
Jae-Hong
JH
Lim
Ashok
A
Mulchandani
Nosang V
NV
Myung
D004586:Electrophoresis / Q000379:methods; D037742:Nanotubes, Carbon
D037742:Nanotubes, Carbon