Fabrication of Highly Sensitive Room Temperature Operated No2 Gas Sensor Using Back Gated 2d-Mos2 Fets

Atomically thin layered semiconductors such as Molybdenum Sulphide (MoS 2 ) have emerged as potential candidate for trace level detection of chemicals owing to their innate very high surface to volume ratio. Present work focusses on the fabrication of room temperature operated Nitrogen dioxide (NO 2 ) gas sensor exploiting MoS 2 as gas sensing matrix. Three different sensor structures, (i) Au/Cr/single layer MoS 2 /Si 3 N 4 /Si, (ii) Au/Cr/four-layer MoS 2 /Si 3 N 4 /Si, and Au/Cr/ten-layer MoS 2 /Si 3 N 4 /Si were fabricated and gas sensing measurements were carried out for different NO 2 gas concentrations. Effect of NO 2 gas adsorption on MoS 2 surface was explained using realignment of energy band diagram. Sensing response (%) for Au/Cr/four-layer MoS 2 /Si 3 N 4 /Si structure was found to be maximum as compared to case of single layer and ten-layer structure and corresponding sensing mechanism has been investigated in detail. Response and recovery time of fabricated Au/Cr/four-layer MoS 2 /Si 3 N 4 /Si sensor were found to be 24sec and 41 sec respectively, and cross selectivity measurements were performed and sensor was found to be highly selective towards NO 2 gas