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Anti‐Stokes Photoluminescence of Monolayer WS2

Pierret, Aurélie; Tornatzky, Hans; Maultzsch, Janina

Inst. Festkörperphysik

Anti‐Stokes photoluminescence excitation of a WS2 monolayer flake between 10 and 300 K is reported herein. Even with continuous‐wave lasers at low power, the emission of the exciton at excitation 100 meV below its emission energy at room temperature is observed. A mechanism which involves the trions as the intermediate state is proposed, leading to an efficient up‐conversion process. In addition, it is demonstrated that phonons are the source of the additional energy needed by the system. Overall, the results provide evidence that anti‐Stokes luminescence in transition metal dichalcogenides is very efficient.