title: Quantum-Confined Stark Effect of Individual Defects in a van der Waals Heterostructure.
abstract: The optical properties of atomically thin semiconductor materials have been widely studied because of the isolation of monolayer transition metal dichalcogenides (TMDCs). They have rich optoelectronic properties owing to their large direct bandgap, the interplay between the spin and the valley degree of freedom of charge carriers, and the recently discovered localized excitonic states giving rise to single photon emission. In this Letter, we study the quantum-confined Stark effect of these localized emitters present near the edges of monolayer tungsten diselenide (WSe2). By carefully designing sequences of metallic (graphene), insulating (hexagonal boron nitride), and semiconducting (WSe2) two-dimensional materials, we fabricate a van der Waals heterostructure field effect device with WSe2hosting quantum emitters that is responsive to external static electric field applied to the device. A very efficient spectral tunability up to 21 meV is demonstrated. Further, evaluation of the spectral shift in the photoluminescence signal as a function of the applied voltage enables us to extract the polarizability volume (up to 2000 Å3) as well as information on the dipole moment of an individual emitter. The Stark shift can be further modulated on application of an external magnetic field, where we observe a flip in the sign of dipole moment possibly due to rearrangement of the position of electron and hole wave functions within the emitter.
authors.forename: Chitraleema
authors.identifier: 0000-0003-2393-0481
authors.initials: C
authors.lastname: Chakraborty
authors.forename: Kenneth M
authors.identifier: 0000-0002-7762-6971
authors.initials: KM
authors.lastname: Goodfellow
authors.forename: Sajal
authors.initials: S
authors.lastname: Dhara
authors.affiliation: Department of Physics, Rensselaer Polytechnic Institute , Troy, New York 12180, United States.
authors.forename: Anthony
authors.initials: A
authors.lastname: Yoshimura
authors.affiliation: Department of Physics, Rensselaer Polytechnic Institute , Troy, New York 12180, United States.
authors.forename: Vincent
authors.initials: V
authors.lastname: Meunier
authors.affiliation: Department of Physics, University of Rochester , Rochester, New York 14627, United States.
authors.forename: A Nick
authors.initials: AN
authors.lastname: Vamivakas
keywords: Quantum confined Stark effect; defects; monolayer tungsten diselenide; single photon emitter; transition metal dichalcogenide; van der Waal’s heterostructure