Lateral MoS2 heterostructure for sensing small gas molecules

Abstract

The potential of a two-dimensional (2D) molybdenum disulfide (MoS2) lateral heterostructure in sensing small gas molecules is being assessed on the basis of quantum mechanical calculations. This heterostructure combines two phases of MoS2, namely, a metallic ribbon embedded within the semiconducting MoS2 phase. In this work the influence on the electronic structure of this 2D material due to the adsorption of gas molecules is investigated. Specifically, the adsorption of NO, NO2, O2, CO, and CO2 on the MoS2 heterostructure is studied. Overall, gas-specific peaks in the electronic features of the 2D material could be clearly revealed, while differences were also found for a gas adsorption close to the interfaces of the material. The “poisonous” nitrogen oxide molecules showed a stronger adsorption on the material but could very well be distinguished over the “healthy” molecular oxygen gas. The complexity of the heterostructure provides more rich gas adsorption characteristics over the single-phase material and is thereby expected to show an enhanced sensitivity due to the increased statistics and the wider window of gate voltages that can be applied. This work provides a proof of principles on the high relevance of the 2D MoS2 heterostructure in view of response materials in gas detectors.