Controllable band offset in monolayer MoSe2 driven by surface termination and ferroelectric field of BiFeO3(0001) substrate

Highlights: • Nonvolatile carrier modulation and ferroelectric field effect is predicted in MoSe₂/BiFeO₃(0001) hybrid system. • Fermi level of MoSe₂ monolayer shows dependence on surface termination and polarization direction of BiFeO₃(0001). • MoSe₂ homojunctions can be fabricated in MoSe₂/BiFeO₃(0001) by local surface chemistry or domain structure engineering. • MoSe₂/BiFeO₃(0001) heterointerface develops into energetically metastable state by switching polarization direction. • Remarkable ferroelectric field effect is predicted in MoSe₂/BiFeO₃(0001) due to distinct interface charge transfer. Integration of 2D van der Waals crystals into ferroelectric materials is a reliable way for the technological leap toward next-generation (opto)electronic applications. In present work, first-principles density functional theory calculations were performed to describe nonvolatile carrier modulation and ferroelectric field effect caused by interface coupling of MoSe₂ monolayer with ferroelectric BiFeO₃(0001) substrate. The Fermi level of MoSe₂ monolayer on BiFeO₃(0001) surface showed strong dependence on surface termination and polarization direction. Furthermore, polarization switching made MoSe₂/BiFeO₃(0001) heterointerface evolve into energetically metastable state and remarkable ferroelectric field effect on band offset in MoSe₂ monolayer was observed due to distinct interface charge transfer. Therefore, the results of this work open up new prospects for surface chemistry and domain structure engineering of MoSe₂ homojunctions for MoSe₂/BiFeO₃(0001)-based ferroelectric field effect devices.