Electric-Field Sensor Based on Multilayer-MoS ₂ /Multilayer-Graphene Heterostructure with Built-In Tensile Strain

High Resolution Image Download MS PowerPoint Slide We report a highly sensitive electric field (E-field) sensor based on a multilayer MoS 2 /multilayer graphene (ML-MoS 2 /MLG) heterostructure with built-in tensile strain. The MLG functions as a bottom source-drain contact, thereby enhancing the charge injection into the ML-MoS 2 channel. The unique device geometry further induces tensile strain in the ML-MoS 2 channel by bending it over the MLG edge, which improves the carrier mobility through reduced electron–phonon scattering. As a result, the ML-MoS 2 /MLG device achieves an average carrier mobility of 75.7 cm 2 V –1 s –1, with values up to ∼108 cm 2 V –1 s –1 at room temperature, significantly exceeding that of conventional metal-contacted MoS 2 devices. Upon exposure to external E-fields, the device exhibits polarity-dependent variations in the drain current arising from field-induced carrier transfer between the ML-MoS 2 channel and trap states at the SiO 2 /channel interface. The E-field sensitivity, defined as the relative change in drain current, increases linearly with the E-field magnitude. Owing to the enhanced charge injection and improved carrier mobility, the ML-MoS 2 /MLG device demonstrates superior E-field sensing performance, achieving a sensitivity around three times that of metal-contacted MoS 2 devices. Notably, the minimum detectable E-field reaches ∼100 V/m, highlighting its potential for atmospheric E-field monitoring toward lightning detection applications.