Humidity sensing characteristics of graphene and MoS2 as well as their heterostructures with different stacking configurations

Abstract

Ultra-high specific surface area of two-dimensional (2D) materials boosts the development of 2D material films-based electron devices in gas sensing and humidity sensing. Here, we constructed four distinct humidity sensor architectures based on atomically thin graphene and molybdenum disulfide, encompassing configurations of monolayer graphene, monolayer MoS2, graphene/MoS2 heterostructures, and reverse-stacked MoS₂/graphene heterostructures. And we systematically elucidated the evolution of humidity response characteristics of 2D membranes above during the transition from individual materials to their heterostructures. The results revealed that within range from 15% RH to 55% RH, the monolayer MoS2-based humidity sensor demonstrated exceptional response characteristics with a remarkable resistance change rate (ΔR/R0) of 271.1%, significantly surpassing the resistance change rates of the humidity sensors based on monolayer graphene (1.98%), graphene/MoS2 heterostructures (1.69%), and MoS2/graphene heterostructures (1.16%). This pronounced performance disparity highlighted the crucial role of two-dimensional material interface engineering in modulating humidity sensing capabilities, providing important theoretical foundations and practical guidance for developing high-performance humidity sensors based on two-dimensional materials.