Development of NH₃ Gas Sensors at Room Temperature Based on Modified Carbon Nanotubes

Abstract

Multiwalled carbon nanotubes (CNTs) were modified with the Hummers method and coated onto Pt electrodes patterned on SiO₂/Si(001) surface to fabricate chemical sensors. The modified CNTs showed a different structure and increased number of defects compared with pristine CNTs, these properties facilitated the adsorption of NH₃ gas molecules on the CNT surfaces. NH₃ gas sensing results indicate that the sensor exhibited an enhanced response to gas at room temperature. The response of the modified CNT-based sensor was 10 times higher than that of pristine CNT-based sensors.

Fig. 3 Transient responses of the modified CNT-based sensor after five cycles of on/off exposure to 50 ppm NH₃ gas concentration at room temperature (a) and an on/off cycle of the sensor’s response (b). The sensor showed good responses to the NH₃ gas and more 10 times higher than that of pristine CNT-based sensor.