Pd- and Au-Decorated MoS2 Gas Sensors for Enhanced Selectivity

Abstract

To date, chemoresistive gas sensors based on metal oxide semiconductors (MOS) have been the most attractive sensor types for the practical application. However, with the emerging concept of Internet of Everything, high operating temperatures over 300 °C of the gas sensors based on MOS must be reduced to achieve low power consumption and overcome a limited battery capacity of mobile devices. The 2-dimensional materials like MoS2 have been, therefore, one of the most recently studied materials for gas sensors with capability of operation at significantly lower temperatures. However, lacking selectivity toward various target gas species limited their application to gas sensors. Herein, we investigated the effects of noble metals (Pd and Au) decoration on the gas sensing properties of MoS2 thin films. Due to the electronic sensitization of the noble metal catalysts and the formation of Pd hydride, overall gas responses and selectivity were significantly improved toward tests gas species. These results provide clear understandings on the effects of the surface noble metal catalysts on gas sensing properties of MoS2.