Bifunctional sensing characteristics of chemical vapor deposition synthesized atomic-layered MoS2.

Two-dimensional (2D) molybdenum disulfide (MoS2) atomic layers have a strong potential to be adopted for 2D electronic components due to extraordinary and novel properties not available in their bulk foams. Unique properties of the MoS2, including quasi-2D crystallinity, ultrahigh surface-to-volume, and a high absorption coefficient, have enabled high-performance sensor applications. However, implementation of only a single-functional sensor presents a limitation for various advanced multifunctional sensor applications within a single device. Here, we demonstrate the charge-transfer-based sensitive (detection of 120 ppb of NO2) and selective gas-sensing capability of the chemical vapor deposition synthesized MoS2 and good photosensing characteristics, including moderate photoresponsivity (∼71 mA/W), reliable photoresponse, and rapid photoswitching (<500 ms). A bifunctional sensor within a single MoS2 device to detect photons and gas molecules in sequence is finally demonstrated, paving a way toward a versatile sensing platform for a futuristic multifunctional sensor.