Modeling of the 2D-materials hybrid nanostructures based on ferroelectric polymer PVDF/P(VDF-TrFE) and MoS2 Dichalcogenide

Abstract

Transition metal dichalcogenide MoS₂ monolayers is very promising for many applications, especially in the fields of optics as emitters and detectors, in electronics as transistors. It is first of all due that they have a direct band gap E_g, which is dependent on external applied electric fields.

To create such an electric field, it is proposed to use the field induced polarization of ferroelectric polymers such as PVDF and P(VDF-TrFE). These polymers in the ferroelectric phase are capable to create significant polarization in very thin layers, about 5 Å. By combining such ferroelectric layers and MoS₂ layers, hybrid nanostructures can be created, that are convenient for design of new photodetectors with controlled properties. The prominent properties of this hybrid structure arise and benefit namely from the ferroelectric-polarization-induced ultra-high electric field of the PVDF or P(VDF-TrFE), that impact on MoS₂ layers and control the band gap E_g.

In this work, we simulate such a hybrid structure based on PVDF and MoS₂ layers and study their features and properties. For calculating MoS₂, the methods of density functional theory (DFT) are used, implemented in the VASP program. Semi-empirical methods based on the HyperChem software package are used to model and study both individual layers of the hybrid structure and the features of their joint interaction. The results obtained convincingly show a strong influence on the width of the MoS₂ bandgap E_g from the side of the PVDF layers, creating polarization P and an electric field E, which affects MoS₂ layers. In addition, the dependence of the band gap E_g under the action of electric field E from the distance between the layers PVDF and MoS₂ has been established.