Highly sensitive two-dimensional MoS ₂ gas sensor decorated with Pt nanoparticles

Abstract

A two-dimensional molybdenum disulfide (MoS 2 )-based gas sensor was decorated with Pt nanoparticles (NPs) for high sensitivity and low limit of detection (LOD) for specific gases (NH 3 and H 2 S). The two-dimensional MoS 2 film was grown at 400°C using metal organic gas vapour deposition. To fabricate the MoS 2 gas sensor, an interdigitated Au/Ti electrode was deposited using the electron beam (e-beam) evaporation method with a stencil mask. The MoS 2 gas sensor without metal decoration sensitively detects NH 3 and H 2 S gas down to 2.5 and 30 ppm, respectively, at room temperature (RT). However, for improved detection of NH 3 and H 2 S gas, we investigated the functionalization strategy using metal decoration. Pt NP decoration modulated the electronic properties of MoS 2 , significantly improving the sensitivity of NH 3 and H 2 S gas by 5.58× and 4.25×, respectively, compared with the undecorated MoS 2 gas sensor under concentrations of 70 ppm. Furthermore, the Pt NP-decorated MoS 2 sensor had lower LODs for NH 3 and H 2 S gas of 130 ppb and 5 ppm, respectively, at RT.