Fabrication of gas ionization sensor using carbon nanotube arrays grown on porous silicon substrate

Nikfarjam, Alireza; zad, Azam Iraji; Razi, F.; Mortazavi, Seyedeh Zahra

doi:10.1016/j.sna.2010.06.015

Cited by 37 publications

(13 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the applied extracting voltage U e was lower than the breakdown voltage, our triple-electrode ionization gas sensor worked in a non-self-sustaining discharge state to reduce the damage to the CNTs caused by the electric breakdown. Thus, the non-self-sustaining discharge current could be used to measure the gas concentration with good stability, which had been demonstrated using the gold nanowires anode [ 24 , 25 ] and the CNTs-based cathode [ 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Selective Detection of NO and NO2 with CNTs-Based Ionization Sensor Array

Song

Wang

2018

Micromachines

View full text Add to dashboard Cite

The accurate detection of NOx is an important issue, because nitrogen oxides are not only environmental pollutants, but also harm to human health. An array composed of two carbon nanotubes (CNTs)-based ionization sensors with different separations is proposed for NO and NO2 selective detection. The experimental results indicate that the CNTs-based ionization sensor has an intrinsic, monotonically decreasing response to NO or NO2. The sensor with 80 µm separations and 100 µm separations exhibited the highest sensitivity of −0.11 nA/ppm to 300 ppm NO and −0.49 nA /ppm to 70 ppm NO2, respectively. Although the effect of the NO2 concentration on the NO response is much stronger than that of NO on NO2, the array of these two sensors still exhibits the ability to simultaneously detect the concentrations of NO and NO2 in a gas mixture without component separation.

show abstract

Section: Resultsmentioning

confidence: 99%

Selective Detection of NO and NO2 with CNTs-Based Ionization Sensor Array

Song

Wang

2018

Micromachines

View full text Add to dashboard Cite

show abstract

“…This arises from the secondary electron emission induced by heavy bombardment of the positive ions on the nanotube cathode. Higher current density resulted in shorter life-span of nanotubes and multi-valued sensitivity of double-electrode structure234567891011.…”

Section: Discussionmentioning

confidence: 99%

“…Our study overcame a key barrier of double-electrode and tripolar electrode ionic gas sensors, that is multi-valued sensitivity234567891011 to gas concentration at 1 atm operating pressure. Through design of the triple-electrode gas sensor and careful control of the distances from the extracting electrode to the cathode and the collecting electrode as well as the field direction and the voltages between them, we were able to significantly reduce ion bombardment on the carbon nanotube cathode, hence increase field strength at lower voltage near the tips without quick tip damaging, which leads to a single-valued sensitivity in a wide range.…”

Section: Discussionmentioning

confidence: 99%

“…In 2001, carbon nanotube film was used to fabricate a double-electrode discharge gas sensor in our lab1, which triggered an explosion of research on carbon nanotube based gas sensors12345678910111213. Unfortunately, these gas sensors exhibited multi-valued sensitivity of breakdown voltage or discharge current in response to targeted gas component at 1 atm total operating pressure, therefore their applications are limited because a single-valued sensitivity14151617181920 to detection target is required for gas sensors.…”

mentioning

confidence: 99%

“…Additionally, the sensors in this configuration of double-electrode operated in self-sustaining discharge states, in which positive ions heavily bombard the cathode comprised of either nanotubes or a metal plate. In case of either a carbon nanotube cathode or a nanotube anode is used, current density can rise to a considerably large value around 100 A/m 2 , resulting in nanotube film damage21 and a short operating life1234567891011.…”

mentioning

confidence: 99%

See 2 more Smart Citations

High-performance gas sensors with temperature measurement

Zhang

et al. 2013

Sci Rep

View full text Add to dashboard Cite

There are a number of gas ionization sensors using carbon nanotubes as cathode or anode. Unfortunately, their applications are greatly limited by their multi-valued sensitivity, one output value corresponding to several measured concentration values. Here we describe a triple-electrode structure featuring two electric fields with opposite directions, which enable us to overcome the multi-valued sensitivity problem at 1 atm in a wide range of gas concentrations. We used a carbon nanotube array as the first electrode, and the two electric fields between the upper and the lower interelectrode gaps were designed to extract positive ions generated in the upper gap, hence significantly reduced positive ion bombardment on the nanotube electrode, which allowed us to maintain a high electric field near the nanotube tips, leading to a single-valued sensitivity and a long nanotube life. We have demonstrated detection of various gases and simultaneously monitoring temperature, and a potential for applications.

show abstract