Feasibility of ultra-sensitive 2D layered Hall elements

A Hall effect sensor is an analog transducer that detects a magnetic flux. The general requirements for its high magnetic sensitivity in conventional semiconductors are high carrier mobility and ultrathin conduction channel in the material’s and the device’s point of view. Recently, graphene Hall elements (GHEs) that satisfy those conditions have been demonstrated with a current-normalized magnetic sensitivity (S_I) superior to that of Si-based Hall sensors. Nevertheless, the feasibility of Hall elements based on an atomically thin monolayer transition metal dichalcogenide (TMD) system has not been studied thus far, although such a system would further enable a largely suppressed 2D carrier density. Herein, we show the strategy how to achieve the highest possible S_I in a TMD-based Hall element in terms of the device structure as well as the operating bias condition. A monolayer molybdenum disulfide Hall element (MHE) on a hexagonal boron nitride (h-BN) thin film was fabricated, and the best bias conditions were selected based on the analytical model for zero-field transconductance data. Finally, the maximum S_I of MHE/h-BN was found to be ~3000 V/AT. This work sheds light on the feasibility of TMD-based Hall element systems.