Excitons in a mirror: Formation of "optical bilayers" using MoS 2 monolayers on gold substrates

Jan Mertens, Yumeng Shi, Alejandro Molina-Sánchez, Ludger Wirtz, Hui Ying Yang, Jeremy J. Baumberg

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

We report coupling of excitons in monolayers of molybdenum disulphide to their mirror image in an underlying gold substrate. Excitons at the direct band gap are little affected by the substrate whereas strongly bound C-excitons associated with a van-Hove singularity change drastically. On quartz substrates only one C-exciton is visible (in the blue) but on gold substrates a strong red-shifted extra resonance in the green is seen. Exciton coupling to its image leads to formation of a "mirror biexciton" with enhanced binding energy. Estimates of this energy shift in an emitter-gold system match experiments well. The absorption spectrum of MoS 2 on gold thus resembles a bilayer of MoS 2 which has been created by optical coupling. Additional top-mirrors produce an "optical bulk."

Original languageEnglish (US)
Article number191105
JournalApplied Physics Letters
Volume104
Issue number19
DOIs
StatePublished - May 12 2014

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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