Highly sensitive and low detection limit of resistive NO2 gas sensor based on a MoS2/graphene two-dimensional heterostructures

The atomic-layer thickness of two-dimensional (2D) materials allows efficient interaction with gas molecules, promotes charge transfer inside these materials, and allows fast absorption/desorption of gas molecules on their surface. 2D materials such as graphene, transition metal dichalcogenides (e.g., MoS2), and phosphorene are promising gas sensor components, exhibiting the advantages of high surface-to-volume ratio, low noise levels, and sensitivity of electronic properties to changes in the surrounding environment. Herein, we performed large-scale thermal chemical vapor deposition (CVD) of MoS2 on graphene and used the prepared hybrid to construct a resistive NO2 gas sensor, which showed high sensitivity, good selectivity and a low detection limit (0.2 ppm), exhibiting the additional advantages of broad detection (0.2-100 ppm) and working temperature (25-200 degrees C) ranges. The excellent performance of the above sensor was ascribed to the synergistic effects of MoS2 and graphene, with the high active surface of MoS2 leading to the exposure of a large fraction of edge sites and thus achieving excellent activity.