Miniaturized gas ionization sensors using carbon nanotubes.
Gas sensors operate by a variety of fundamentally different mechanisms. Ionization sensors work by fingerprinting the ionization characteristics of distinct gases, but they are limited by their huge, bulky architecture, high power consumption and risky high-voltage operation. Here we report the fabrication and successful testing of ionization microsensors featuring the electrical breakdown of a range of gases and gas mixtures at carbon nanotube tips. The sharp tips of nanotubes generate very high electric fields at relatively low voltages, lowering breakdown voltages several-fold in comparison to traditional electrodes, and thereby enabling compact, battery-powered and safe operation of such sensors. The sensors show good sensitivity and selectivity, and are unaffected by extraneous factors such as temperature, humidity, and gas flow. As such, the devices offer several practical advantages over previously reported nanotube sensor systems. The simple, low-cost, sensors described here could be deployed for a variety of applications, such as environmental monitoring, sensing in chemical processing plants, and gas detection for counter-terrorism.
Modi
Ashish
A
Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Koratkar
Nikhil
N
Lass
Eric
E
Wei
Bingqing
B
Ajayan
Pulickel M
PM
D000388:Air; D000641:Ammonia / Q000032:analysis / Q000737:chemistry; D001128:Argon / Q000737:chemistry; D015374:Biosensing Techniques; D002244:Carbon; D005740:Gases; D036103:Nanotechnology; D010100:Oxygen / Q000737:chemistry; D012680:Sensitivity and Specificity
D005740:Gases; D001128:Argon; D002244:Carbon; D000641:Ammonia; D010100:Oxygen