Improving sensing properties of entangled carbon nanotube-based gas sensors by atmospheric plasma surface treatment

• Published in: Microelectronic engineering Vol. 232; p. 111403
• Main Authors: M. Santhosh, Neelakandan, Vasudevan, Aswathy, Jurov, Andrea, Korent, Anja, Slobodian, Petr, Zavašnik, Janez, Cvelbar, Uroš
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2020; Elsevier BV
• Subjects: Carbon; Composite; Ethanol; Gas detectors; Gas sensor; Gas sensors; Helium; Multi wall carbon nanotubes; Multi-walled carbon nanotubes; Nanotubes; Plasma; Plasma-treatment; Polyurethane resins; Response time; Sensitivity; Sensor response; Surface roughness; Surface treatment; Gas sensor; Composite; Multi-walled carbon nanotubes; Plasma-treatment; Sensor response
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2020.111403

Entangled multi-walled carbon nanotubes (MWCNTs) on polyurethane (PUR) after Ar plasma-treatment and He plasma-treatment have been tested as gas sensors for ethanol sensing. It was found that plasma-treated sensors exhibit higher sensitivity compared to the non-treated samples along with different ethanol concentration. Non-treated sensors exhibit similar sensor response with the increase in ethanol concentration, while Ar plasma-treated sensors displays ~5 times improvement and He plasma-treated sensors show ~3 times improvement with an increase in ethanol concentration. The sensitivity of the plasma-treated sensors is also stable for following two-weeks after the preparation compared to the non-treated sensor. Entangled nanotube network exhibits a significant shift in the baseline resistance after both plasma-treatments. The response time of the sensor was increased after the plasma-treatment, while the recovery was rather quick. Surface analyses revealed that plasma-treatment did not make any significant morphological changes. Thus, the improvements in stability and sensitivity after plasma-treatment are attributed to the plasma-enhanced surface modification and formation of functional bonds on the surface of nanotubes, which are sensitive to the ethanol vapour. [Display omitted] •Sensing properties of the entangled carbon nanotube-based sensors were improved by atmospheric jet plasma surface treatment.•Plasma surface-treatment resulted in a significant shift in the baseline resistance and enhancement of stability of the sensors.•Influence of plasma-treatment on the sensor response and recovery time at room temperature was investigated.