Highly sensitive two-dimensional MoS₂ gas sensor decorated with Pt nanoparticles

A two-dimensional molybdenum disulfide (MoS₂)-based gas sensor was decorated with Pt nanoparticles (NPs) for high sensitivity and low limit of detection (LOD) for specific gases (NH₃ and H₂S). The two-dimensional MoS₂ film was grown at 400°C using metal organic gas vapour deposition. To fabricate the MoS₂ gas sensor, an interdigitated Au/Ti electrode was deposited using the electron beam (e-beam) evaporation method with a stencil mask. The MoS₂ gas sensor without metal decoration sensitively detects NH₃ and H₂S gas down to 2.5 and 30 ppm, respectively, at room temperature (RT). However, for improved detection of NH₃ and H₂S gas, we investigated the functionalization strategy using metal decoration. Pt NP decoration modulated the electronic properties of MoS₂, significantly improving the sensitivity of NH₃ and H₂S gas by 5.58× and 4.25×, respectively, compared with the undecorated MoS₂ gas sensor under concentrations of 70 ppm. Furthermore, the Pt NP-decorated MoS₂ sensor had lower LODs for NH₃ and H₂S gas of 130 ppb and 5 ppm, respectively, at RT.