Carbon Nanotubes as Active Components for Gas Sensors

Table 1

Summary of gas-sensing performance of pristine CNT gas sensors. (Note: N/S = Not-stated.)

CNT type	Sensor configuration	Targeted analytes	Detection limit	Response time	Recovery time	Reference
S-SWCNT	FET	NO2, NH3	2 ppm NO2, 0.1% NH3	<10 min	∼1 h (200^∘C)	[7]
SWCNTs	Resistor	NO2, Nitrotoluene	44 ppb NO2, 262 ppb Nitrotoluene	10 min	10 min (UV)	[14]
SWCNTs	Resistor	NH3	5 ppm	∼10 min	∼20 min (80^∘C)	[16]
SWCNTs	Resistor	NH3	5 ppm	∼10 min	∼10 min (70^∘C)	[17]
MWCNTs	Capacitor and Resistor	NH3	10 ppm	2-3 min	several days (100^∘C in vacuum)	[18]
MWCNTs	Resistor	NH3	2500 ppm	N/S	N/S	[19]
MWCNTs	FET	NO2	50 ppm	∼500 s	∼10 min (10 V bias potential)	[20]
MWCNTs	Resistor	SO2, HF	10 ppm SO2, 4 ppm HF	N/S	N/S	[21]
MWCNTs	Electrochemical Gas sensor	Cl2	100 ppm	∼150 s	∼150 s	[22]
ACNTs	Resistor	NO2	10 ppb	∼60 min	∼60 min (165^∘C)	[26]
ACNTs	Resistor	NO2	10 ppm	N/S	N/S	[27]
ACNTs	Resistor	NO, NO2	2 ppm NO, 2 ppm NO2	N/S	∼20 min (150^∘C and UV)	[28]
ACNTs	Resistor	NH3	∼0.1%	N/S	N/S	[29]
ACNTs	FET	N2	50 mTorr	N/S	N/S	[30]