Graphene Films and Ribbons for Sensing of O₂, and 100 ppm of CO and NO₂ in Practical Conditions

Abstract

Graphene films and ribbons were grown on Ni-coated Si substrates using the microwave plasma enhanced chemical vapor deposition method. We report the structure, morphology, and quality of graphene films and ribbons. The semiconducting nature of the CVD-grown graphene was observed by studying resistance−temperature variation in the range 25 to 200 °C, using the four-point probe method. Graphene exhibited an increase of resistance upon exposure of CO and a decrease in resistance upon pure O2 and NO2 exposures. It was observed that graphene films show sensor signal ∼3 and 35 for 100 ppm of CO and 100 ppm of NO2 whereas the graphene ribbons show the sensor signal values of 1.5 and 18 for 100 ppm of CO and 100 ppm of NO2. The gas sensor mechanism was observed to be mainly dependent on the charge carrier transfer on conducting graphene surfaces caused by the adsorption of gases.

Nanoelectronics and nanosensors for space exploration

“…Graphene has also been successfully used in chemical sensors for the identifi cation of similar gases and vapors. [58][59][60][61][62] Whereas graphene and CNTs allow room-temperature operation of chemiresistors, FETs, or other sensor variations, metal oxide materials, even in the form of nanowires, mostly require operation at elevated temperatures ( ∼ 200°C) to obtain comparable sensitivities and response times. 63 Our group has been developing SWCNT-based chemical sensors for nearly a decade.…”

Flexible NO2gas sensor using multilayer graphene films by chemical vapor deposition

“…With that goal in mind, many researchers have developed high-performance NO 2 gas sensors using reduced graphene oxide sheets, obtained from high temperature annealing [9] or a chemical conversion with hydrazine [10] and ascorbic acid [11], for application as a low-cost, simple and practical sensor device. More recently, Joshi et al [12] reported a NO 2 gas sensor based on graphene films and ribbons grown on Ni-coated Si substrates using the microwave plasma enhanced chemical vapor deposition (MPECVD) method. In spite of the potential advantages of the CVD-grown graphene films for novel gas sensors, their sensitivity and response time was relatively weak and not yet DOI: http://dx.doi.org/ DOI:10.5714/CL.2013.14.…”

Ultrasensitive room temperature NH3 sensor based on a graphene–polyaniline hybrid loaded on PET thin film

“…Since the sensing process of such sensor involves adsorption/desorption phenomena and deprotonation at the interface, the large specific surface area of gas sensing materials is crucial to maintain their high sensing performance. 24 2) The rGO sheets provide high carriers mobility at room temperature, which results in the rapid increase of the hybrid resistance, that is, reduces the response time of hybrid toward NH3 gas; 25 3) When rGO sheets expose to NH3 gas, it will cause decrease in the number of charge carriers due to the electron withdrawing nature of absorbed water, which induce hole-like carriers, 26 resulting in an increase in resistance, thus increasing the sensitivity to NH3 gas 26 ; 4) The electron transfer may occur between the conjugated PANI and rGO through π-π interaction during the sensing process, and consequently increases the sensing performance of hybrid. 27 However, detailed understanding for the role of rGO in the sensing mechanism of hybrid is still lacking.…”