Non-trivial designs and fabrication of chemiresistive gas sensors towards superior ammonia sensing performance

Abstract

Implementation of high-end fabrication techniques e.g. e-beam lithography, photolithography etc. hinders realization of cost effective chemiresistive gas sensors. Here, for the first time, we have fabricated four different non-trivial designs of SnS2 based chemiresistive sensors namely scratched fluorine doped tin oxide (FTO) based sensor, aluminium rod based sensor, spiral copper wire based sensor and FTO/porous nickel foil based sensor towards NH3 detection at room temperature using easy and affordable processes. The new strategies of designing different sensor structures are to increase the exposed junction region (P) between sensing layer & electrode and decrease the resistance (R) of the sensor. Scratched FTO based sensor with no exposed region exhibits poor sensing performance whereas the other three sensors exhibit progressively enhanced performance (in terms of response, response time and limit of detection) with the increase of P/R ratio. Aluminium rod based sensor (P/R= 1.07 ×10−6 cm/Ω) offers response of 6.46 (at 225 ppm), 71 s of response time, 45 ppm of limit of detection whereas FTO/porous nickel foil based sensor (P/R= 13.93 ×10−6 cm/Ω) exhibits highest response of 49.5, response time of 49.2 s and limit of detection down to 10 ppm. This novel approach towards realizing a cost effective and superior gas sensor may be useful for the application in sensor technology.