Exciton Emissions in Bilayer WSe2 Tuned by the Ferroelectric Polymer

In this work, a hybrid structure of multilayer transition-metal dichalcogenides (TMDs) and a ferroelectric polymer is designed to achieve passive control of optical properties in situ. The electrical polarization in the ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) polymer can regulate the photoluminescence (PL) in bilayer WSe2. The total PL emission intensity is substantially suppressed or enhanced under large gate voltage in bilayer WSe2. This is because electrons transfer between the conduction band K valley and the conduction band A valley by the electrostatic field in the P(VDF-TrFE) polymer. This electron transfer further adjusts the proportion of direct and indirect excitons and, in turn, changes the overall optical radiation efficiency. We also illustrate that the engineered PL originates from the external electric-field-dependent transferred electron effect. The theoretical result matches the experimental data well. This work demonstrates a device platform in which passive regulation is achieved using 2D TMDs modulated by polarized ferroelectric materials.

Automated summary

In this study, a hybrid structure combining multilayer TMDs and a ferroelectric polymer is utilized to achieve passive control of optical properties. By modulating the electrical polarization in the ferroelectric polymer, the photoluminescence intensity in bilayer WSe2 can be regulated, leading to changes in the overall optical radiation efficiency.