Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics

High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS 2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS 2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS 2 strain/force sensor built using a monolayer MoS 2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS 2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical–electronic nanodevices. Two-dimensional transition-metal-dichalcogenide materials should have strong piezoelectric properties, making them useful for nanosensors and piezotronics. Here, the authors experimentally demonstrate the piezoelectric effect in monolayer molybdenum disulfide and show how this can modulate conductivity.