Visualizing giant ferroelectric gating effects in large-scale WSe$_2$/BiFeO$_3$ heterostructures

TL;DR

This study demonstrates large-scale integration of WSe$_2$ with BiFeO$_3$ heterostructures, revealing giant ferroelectric gating effects that significantly alter the electronic properties of the TMD layer.

Contribution

It presents the first large-scale integration of perovskite oxides with transition-metal dichalcogenides, showing giant ferroelectric gating effects on WSe$_2$ properties.

Findings

Giant energy shift of up to 0.75 eV induced by ferroelectric polarization

Successful large-scale transfer of WSe$_2$ onto BiFeO$_3$

Visualization of electronic structure changes via photoemission spectroscopy

Abstract

Multilayers based on quantum materials (complex oxides, topological insulators, transition-metal dichalcogenides, etc) have enabled the design of devices that could revolutionize microelectronics and optoelectronics. However, heterostructures incorporating quantum materials from different families remain scarce, while they would immensely broaden the range of possible applications. Here we demonstrate the large-scale integration of compounds from two highly-multifunctional families: perovskite oxides and transition-metal dichalcogenides (TMDs). We couple BiFeO$_3$, a room-temperature multiferroic oxide, and WSe$_2$, a semiconducting two-dimensional material with potential for photovoltaics and photonics. WSe$_2$ is grown by molecular beam epitaxy and transferred on a centimeter-scale onto BiFeO$_3$ films. Using angle-resolved photoemission spectroscopy, we visualize the electronic structure of 1 to 3 monolayers of WSe$_2$ and evidence a giant energy shift as large as 0.75 eV induced by the ferroelectric polarization direction in the underlying BiFeO$_3$. Such a strong shift opens new perspectives in the efficient manipulation of TMDs properties by proximity effects.