Virtual Out-of-Plane Piezoelectric Response in MoS₂ Layers Controlled by Ferroelectric Polarization

The MoS₂ carrier distribution can be controlled with the use of a dielectric environment substrate. Ferroelectric thin films are used to investigate the electrical responses at the MoS₂ layer. The MoS₂/(111)-PbTiO₃ vertical heterostructure is investigated, and the electrical responses, including piezoelectricity, are obtained using piezoresponse force microscopy. The piezoelectric response modifications obtained at the MoS₂ layer on the ferroelectric thin films are a result of the depolarizing effect. In particular, the piezoelectricity enhancement is observed at the 19-layer MoS₂ because of an induced dipole effect. By considering the polarization effects of ferroelectric thin films, the electrical responses at the MoS₂ layers can be controlled, and the interfacial carrier distribution at the interface results in different electrical performances at the MoS₂.