Role of Electric Field on Sensing Mechanism of Carbon Nanotube Based Ammonia Gas Sensor

Mishra, Prabhash; Balyan, Prerna; Harsh,; Islam, S. S.

doi:10.1166/sl.2013.2982

Cited by 12 publications

(6 citation statements)

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“…The high resistance sensors possessed low charge carrier concentration, and thus, they were more sensitive to any change of NH 3 adsorption. Mishra et al [32] supposed 7 Journal of Sensors that the increase of the disorder degree improved the sensor response because a higher defect density increased the number of active sites in which ammonia can be adsorbed. The I D /I G of the five sensors from the third group (the resistance below 3 kΩ) was quite different, 0.44-0.92, but their response did not prove to be dependent on it.…”

Section: Ammonia Adsorption On Carbon Nanostructured Filmsmentioning

confidence: 99%

“…If the sensor recovery is required, it is necessary to employ some method, such as heating [4,40], increasing of gas flow [40], irradiation by infrared light [49], and strong electric field [32] to accelerate it. Preliminary measurements showed that the sensor recovery performed by an air flow increase was insufficient for a complete sensor recovery.…”

Section: Journal Of Sensorsmentioning

confidence: 99%

“…Up to now, the CNT-based NH 3 gas sensors were closely investigated from the performance point of view but the influence of the synthesis conditions of these materials on the sensing properties has not yet been studied. Previous studies were based on the creation of the sensors by the direct deposition of CNTs using only certain conditions [30][31][32][33] without detailed investigation of their synthesis role in the formation of sensor response. The influence of NFC deposition parameters (growth temperature and time) on the materials' properties and NH 3 sensing characteristics is determined.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

et al. 2018

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The ammonia adsorption on the nanostructured carbon thin film was significantly influenced by the choice of deposition temperature and deposition time of thin film synthesis. The thin films were prepared on Si/SiO2 substrates by chemical vapour deposition in Ar/C2H2 gas mixture using iron catalytic nanoparticles. The analysis of the grown layer by the scanning and transmission electron microscopy showed the transition from long multiwalled nanotubes (MWCNTs) to bamboo-like hollow carbon nanofiber structure with the decrease of the deposition temperature from 700 to 600°C. Further, the material was analyzed by energy-dispersive X-ray spectroscopy and Raman spectroscopy confirmed the transition from graphitic sp2 structure to highly defective structure at lower deposition temperature. The resistance of the prepared layer strongly depends on deposition temperature (Td) and deposition time (td). High resistance layer, 38.6 kΩ, was formed at Td 600°C and td 10 min, while at Td 700°C and td 60 min, the resistance decreased to 860 ohms. Such behaviour is consistent with MWCNTs being responsible for the formation of the conductive network. Such system was studied using chemiresistor ammonia gas sensor configuration. The sensor resistance increased when exposed to ammonia in all the cases, but their response varied considerably. A decrease in deposition time, from 60 to 10 min, and the deposition temperature, from 700 to 600°C, led to the 10-fold increase in the sensor response. The measurements carried out at room temperature showed the higher sensor response than the measurements carried out at 200°C. This behaviour can be explained by the change in adsorption-desorption equilibrium at different temperatures. Analysis of dependence of the sensor response on the ammonia concentration proved that the underlying resistance change mechanism is chemisorption of ammonia molecules on the carbon network corresponding to the Langmuir isotherm.

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Section: Ammonia Adsorption On Carbon Nanostructured Filmsmentioning

confidence: 99%

Section: Journal Of Sensorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced Ammonia Adsorption on Directly Deposited Nanofibrous Carbon Films

et al. 2018

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“…Mainly, sensors based on carbon nanomaterials require recovery. This recovery can be carried out using heating [ 87 , 153 , 162 ], an increase in gas flow [ 40 ], a strong electric field [ 206 ], or irradiation by infrared light [ 207 ]. In [ 207 ], a sensor based on graphene decorated with Au nanoparticles was illuminated with infrared radiation (≈2 µW/mm 2 ), which made it possible to recover more than 90% of the original baseline level.…”

Section: Recovery Of Sensorsmentioning

confidence: 99%

Recent Advances in Ammonia Gas Sensors Based on Carbon Nanomaterials

et al. 2021

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This review paper is devoted to an extended analysis of ammonia gas sensors based on carbon nanomaterials. It provides a detailed comparison of various types of active materials used for the detection of ammonia, e.g., carbon nanotubes, carbon nanofibers, graphene, graphene oxide, and related materials. Different parameters that can affect the performance of chemiresistive gas sensors are discussed. The paper also gives a comparison of the sensing characteristics (response, response time, recovery time, operating temperature) of gas sensors based on carbon nanomaterials. The results of our tests on ammonia gas sensors using various techniques are analyzed. The problems related to the recovery of sensors using various approaches are also considered. Finally, the impact of relative humidity on the sensing behavior of carbon nanomaterials of various different natures was estimated.

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“…The normal recovery of CNT based toxic gas sensor is a major problem and lots of studies have been carried out extensively by many researchers [27,28]. The present authors have employed various techniques to get complete recovery [29,30]. Fig.…”

Section: Sensing Performancementioning

confidence: 99%