Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures

Abstract

The intriguing physics of carrier-carrier interactions, which likewise affect the operation of light emitting devices, stimulate the research on semiconductor structures at high densities of excited carriers, a limit reachable at large pumping rates or in systems with long-lived electron-hole pairs. By electrically injecting carriers into WSe${}_2$/MoS${}_2$ type-II heterostructures which are indirect in real and k-space, we establish a large population of typical optically silent interlayer excitons. Here, we reveal their emission spectra and show that the emission energy is tunable by an applied electric field. When the population is further increased by suppressing the radiative recombination rate with the introduction of an hBN spacer between WSe${}_2$ and MoS${}_2$, Auger-type and exciton-exciton annihilation processes become important. These processes are traced by the observation of an up-converted emission demonstrating that excitons gaining energy in non-radiative Auger processes can be recovered and recombine radiatively.

accepted for publication in Nature Communications

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• Opportunities in Electrically Tunable 2D Materials Beyond Graphene: Recent Progress and Future Outlook
• Coupling interlayer excitons to whispering gallery modes in van der Waals heterostructures
• Harnessing Exciton-Exciton Annihilation in Two-Dimensional Semiconductors
• Optical signature of cascade transitions between moiré interlayer excitons
• Exciton-polaritons in multilayer WSe${}_2$ in a planar microcavity
• Large few-layer hexagonal boron nitride flakes for nonlinear optics
• Controlled Interlayer Exciton Ionization in an Electrostatic Trap in Atomically Thin Heterostructures
• Light sources with bias tunable spectrum based on van der Waals interface transistors
• Monolayer Semiconductor Auger Detector
• Role of interface hybridization on induced superconductivity in 1T${}^{\prime }$-WTe${}_2$ and 2H-NbSe${}_2$ heterostructures
• All-optical ultrafast arbitrary rotation of hole orbital qubits with direct phase control
• Electrically modulated light-emitting diodes driven by resonant and antiresonant tunneling between Cr${}_2$Ge${}_2$Te${}_6$ electrodes
• Understanding the Effects of Dielectric Property, Separation Distance, and Band Alignment on Interlayer Excitons in 2D Hybrid MoS2/WSe2 Heterostructures