Regensburg 2016 – scientific programme
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DS: Fachverband Dünne Schichten
DS 5: Two-dimensional Materials
(Joint session of DS and HL, organized by HL)
DS 5.10: Talk
Monday, March 7, 2016, 12:30–12:45, H16
Localized states from WSe2 as promising candidates for new single-photon sources — •Sven Borghardt1, Jhih-Sian Tu1, Florian Winkler2, Detlev Grützmacher1, and Beata Kardynal1 — 1PGI-9, Forschungszentrum Jülich, Jülich, Germany — 2ER-C, Forschungszentrum Jülich, Jülich, Germany
An emission of single photons from WSe2 monolayers (ML) has been recently demonstrated but the origin of the emission is still not clear. The aim of our research is to understand its origin and then control the localized emission in this material to harvest the unique properties of the material for new applications in quantum photonics.
Samples prepared by exfoliation from synthetic crystals and also grown with CVD are measured using polarization resolved µ-photoluminescence (PL) as well as time-resolved PL.
Our results show linearly polarized emission doublet lines with an energy splitting of up to a few meV. The samples show a high density of such lines close to the sample edges. We attribute the linear polarization of the localized states to a mixing of K- and K’-states. There is an evidence of an alignment of the polarization of emission with the crystal lattice. PL from the localized states decays faster with the temperature than the one from the free exciton states. Chemical modification of the samples is further used in an attempt to manipulate the emission from the localized states.