Gate Dependent Electroluminescence of Interlayer Excitons in 2D Semiconductor Heterostructures
ORAL
Abstract
Monolayer transition metal dichalcogenides (TMDs) are two-dimensional (2D) semiconductors characterized by a direct band-gap and large exciton binding energies. Due to the 2D quantum confinement, their heterostructures exhibit a number of novel physical properties. By vertically stacking two different TMD monolayers, we can realize a type II heterostructure. In these heterostructures electrons and holes can be confined in individual layers, forming spatially separated long lived interlayer exciton (IE). In this work, we fabricate dual-gated MoSe2/WSe2 heterostructures encapsulated by boron nitride (BN) with electrical contacts in each layer. By applying forward bias voltage across the vertical junction, we observe gate tunable, near-infrared electroluminescence (EL) of interlayer excitons. By changing the relative doping between WSe2 and MoSe2 we can control the spatial location of EL emission. In addition, we find that EL lifetime is comparable to IE photoluminescence lifetime of ~300ns, showing that we can create long lived IE electrically. Such long lifetimes and spatial control pave the way to fully electrically addressable IE condensates, tunable near-IR excitonic lasers and other novel optoelectronic devices.
*Gordon and Betty Moore foundation, MRSEC and Samsung.
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Presenters
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Kateryna Pistunova
- Department of Physics, Harvard University
- Physics, Harvard University
- Harvard Univ
- Harvard University