Electrostatic Modulation and Mechanism of the Electronic Properties of Monolayer MoS2 via Ferroelectric BiAlO3(0001) Polar Surfaces.

Abstract

In the present work, first-principles density functional theory calculations were carried out to explore the intrinsic interface coupling and electrostatic modulation as well as the effect of ferroelectric polarization reversal in the MoS2/BiAlO3(0001) [MoS2/BAO(0001)] hybrid system. In addition to the interaction mechanism of the large ionic–van der Waals (vdW) coupling, our results indicate that the electronic properties of monolayer MoS2 on the BAO(0001) polar surface can be effectively modulated by reversing the ferroelectric polarization and/or engineering the domain structures of the substrate. Due to the unusual charge transfer between the MoS2 overlayer and the down-polarized ferroelectric BAO(0001) substrate, in the final analysis, the physical mechanism determining the interfacial charge transfer in the MoS2/BAO(0001) hybrid system is attributed to the specific band alignment between the clean BAO(0001) surface and the freestanding monolayer MoS2. Furthermore, our study predicts that MoS2-based ferroelectric field-effect transistors and various types of seamless p–i, n–i, p–n, p+–p, and n+–n homojunctions possessing an extremely steep built-in electric field can be fabricated by reversing the ferroelectric polarization and/or patterning the domain structure of the BAO(0001) substrate.