Fabrication of MoSe2–Graphene Hybrid Nanoflakes for Toxic Gas Sensor with Tunable Sensitivity

Abstract In this work, a selective chemi‐resistive gas sensor of molybdenum diselenide/graphene (MoSe 2 /G) nanoflakes (NF) that detects ammonia (NH 3 ) and nitrogen dioxide (NO 2 ) gas at room temperature is successfully fabricated. The MoSe 2 /G NF based sensor shows good sensitivity (2.476 ppm −1 ) and selectivity to NO 2 in comparison with some VOCs and toxic gases than MoSe 2 NF (2.275 ppm −1 ). But in case of NH 3 gas, it shows a drastic increase in sensitivity of MoSe 2 /G NF (9.115 ppm −1 ) than MoSe 2 NF (2.466 ppm −1 ). The MoSe 2 /G NF shows a low detection limit (11 ppb for NH 3 and 41 ppb for NO 2 ), an outstanding repeatability, and a reliable long‐term device durability (more than eight weeks) significantly. The reason of the significant improvement in gas sensing performance can be attributed mainly due to the addition of graphene in MoSe 2 NF which in turns increases the surface‐to‐volume ratio. It encourages the adsorption of gas molecules on the surface of the material, thereby facilitating the charge transfer process. The superior performance of this gas sensor makes MoSe 2 /G NF a potential candidate for NO 2 and NH 3 gas detection at room temperature. Due to the presence of graphene, MoSe 2 NF becomes less hydrophilic which shows very less effect of humidity effect.