An approach to gas sensing - Suspended carbon nanowire gas sensor measuring localized chemical vapor deposition.
- Iraj Nejad, Professor of Chemistry, Mt. San Antonio College
- Jenny Chen, Professor of Chemistry, Mt. San Antonio College
- Lawrence Kulinsky, Professor of Engineering, University of California Irvine
- Marc Madou, UC Chancellor Professor of Engineering, University of California Irvine
Gas sensors have been under great demand to increase precision, while functioning to detect gases at lower concentrations. Nanosized gas sensors are an answer because they can potentially become faster, require less power input, come with a higher sensitivity, operate at lower temperatures, and become manufactured at a lower cost than contemporary counterparts in the market today. The purpose of a suspended carbon nanowire is to use the same carbon element for heating and measuring changes in resistance that occur in the presence of a detectable cracked gas. At high enough temperatures, metal oxide semiconductors on a nanowire can experience chemical vapor deposition from solution locally. The change of resistance in the suspended carbon nanowire can then be measured in a simple completed circuit. Single suspended carbon nanofibers on carbon silicon dioxide micro-structures were then fabricated by directed electrospinning and subsequent pyrolysis at 900oC. Afterwards, a glass chamber was designed and constructed to inertly operate the nanostructure gas sensor. From the electrochemical results collected, the resistance on the thinnest suspended carbon nanowire with a uniformly cylindrical diameter contributed to the highest change in resistance, from ~110kΩ to ~168kΩ. The implications of a ~50% change at such high gross resistivity implies a success detection by the sensor at a low limit of detection for chemical vapor deposition gas sensing.