Auger recombination of dark excitons in $\mathrm{W}{\mathrm{S}}_2$ and $\mathrm{WS}{\mathrm{e}}_2$ monolayers

Abstract

We propose a novel phonon assisted Auger process unique to the electronic band structure of monolayer transition metal dichalcogenides (TMDCs), which dominates the radiative recombination of ground state excitons in Tungsten based TMDCs. Using experimental and DFT computed values for the exciton energies, spin-orbit splittings, optical matrix element, and the Auger matrix elements, we find that the Auger process begins to dominate at carrier densities as low as $10^{9-10}\mathrm{c}{\mathrm{m}}^{-2}$, thus providing a plausible explanation for the low quantum efficiencies reported for these materials.

arXiv comment5 pages, 2 figures

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• Upconverted electroluminescence via Auger scattering of interlayer excitons in van der Waals heterostructures
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• Bright excitons with negative-mass electrons
• Dark trions and biexcitons in WS2 and WSe2 made bright by e-e scattering
• Excitonic complexes in $n$-doped WS${}_2$ monolayer
• Distinctive signatures of the spin- and momentum-forbidden dark exciton states in the photo-luminescences of strained WSe${}_2$ monolayers under thermalization
• Many-body effects in nonlinear optical responses of 2D layered semiconductors
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• Leaky exciton condensates in transition metal dichalcogenide moiré bilayers
• Monolayer Semiconductor Auger Detector
• Microscopic Theory of Exciton-Exciton Annihilation in Two-Dimensional Semiconductors