LAUSR

The possibility to synergise two-dimensional (2D) materials with 0D nanoparticles has sparked a surge in high performance futuristic electronic devices. Here, we decorated plasmonic Au nanoparticles on surface of chemical vapor deposition (CVD) grown 2D MoS₂ nanosheet and demonstrated bifunctional sensing behaviour within a single device. The plasmonic Au nanoparticles functionalized MoS₂ device showed about ~5 times higher sensitivity to NO₂ than that of pristine MoS₂ at room temperature. The enhanced gas sensing performance was attributed to a combination of Schottky barriers modulation at Au/MoS₂ nanointerfaces and catalytic effects upon exposing the gas analyte. In addition, the device also exhibited enhanced photoresponse with a high photo-responsivity of ~17.6 A/W and a moderate detectivity of ~ ${6.6} \times {10}^{11}$ Jones due to enhanced local plasmonic effects. Finally, photons and gas molecules are detected in sequence, which proved that only a single Au-MoS₂ device exhibited remarkable bifunctional sensing characteristics. Such excellent bifunctional sensing ability of a single Au-MoS₂ device paves the way to integrate the 2D material with plasmonic nanostructures for developing an advanced multifunctional sensor.