Dark exciton-exciton annihilation in monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>WSe</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math>
Daniel Erkensten, Samuel Brem, Koloman Wagner, Roland Gillen, Raül Perea‐Causín, Jonas D. Ziegler, Takashi Taniguchi, Kenji Watanabe, Janina Maultzsch, Alexey Chernikov, Ermin Malić
Abstract
Excitons govern the optical properties of semiconducting transition metal dichalcogenides. At elevated electron-hole densities excitons are subject to efficient exciton-exciton annihilation (EEA), an Auger recombination process that fundamentally limits the performance of optoelectronic devices. Here, the authors combine microscopic modeling with time-resolved photoluminescence measurements to demonstrate the crucial role of dark intervalley excitons for an efficient EEA in WSe${}_{2}$ monolayers. In particular, they find both in theory and experiment a drastic increase in the EEA at intermediate temperatures.