Scalable 2D Molybdenum Disulfide-Based Field Effect Transistor Sensor for Emerging Contaminants Detection

Two-dimensional (2D) materials such as Graphene and Transition Metal Dichalcogenides (TMDs, e.g., MoS₂) are promising candidates for sensor applications due to their large surface-to-volume ratio, nanometer thickness, and significant response to external environmental changes. However, sensors based on these 2D materials always require proper chemical functionalization with a probe molecule or receptor to achieve the selective recognition of target molecules and ions, which involves a complex and difficult process. Here, we developed a hexagonal boron nitride (hBN)-assisted functionalization process for the fabrication of highly scalable, back-gated 2D materials-based field-effect transistor (FET) nanosensors through a single chemistry. The basic idea is to use an hBN layer as an intermediate layer and a pyrene-based molecule as the linker to facilitate the bonding with different types of probe molecules. Given the multiple choice of pyrene-based molecular chemistry, we successfully fabricated arrays of 2D MoS₂-based FET sensors for the sensitive and selective detection of different emerging contaminants, such as organic (e.g., per- and poly-fluoroalkyl substances, PFAS) and inorganic (e.g., Pb²⁺) contaminants of concerns. The results show that low limit-of-detection values of 0.001 ppb and 0.07 ppb have been achieved for the detection of PFAS and Pb²⁺ ions, respectively, which also exhibit promising selectivities. The approach could be easily applied to any other 2D materials, therefore providing a universal pathway towards nanosensor fabrication.