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Proceedings Paper

Low-temperature photocarrier dynamics in single-layer MoS2 flakes
Author(s): T. Korn; G. Plechinger; S. Heydrich; M. Hirmer; F.-X. Schrettenbrunner; D. Weiss; J. Eroms; C. Schüller
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Paper Abstract

The dichalcogenide MoS2, which is an indirect-gap semiconductor in its bulk form, was recently shown to become an efficient emitter of photoluminescence as it is thinned to a single layer, indicating a transition to a direct-gap semiconductor due to confinement effects. With its layered structure of weakly coupled, covalently bonded two-dimensional sheets, it can be prepared, just as graphene, using mechanical exfoliation techniques. Here, we present temperature-dependent and time-resolved photoluminescence (PL) studies of single-layer MoS2 flakes. Some of the flakes are covered with oxide layers prepared by atomic layer deposition (ALD). At low temperatures, we clearly see two PL peaks in the as-prepared flakes without oxide layers, which we may assign to bound and free exciton transitions. The lower-energy, bound exciton PL peak is absent in the oxide-covered flakes. In time-resolved PL measurements, we observe very fast photocarrier recombination on the few-ps timescale at low temperatures, with increasing photocarrier lifetimes at higher temperatures due to exciton-phonon scattering.

Paper Details

Date Published: 15 October 2012
PDF: 6 pages
Proc. SPIE 8456, Nanophotonic Materials IX, 84560H (15 October 2012); doi: 10.1117/12.928067
Show Author Affiliations
T. Korn, Univ. Regensburg (Germany)
G. Plechinger, Univ. Regensburg (Germany)
S. Heydrich, Univ. Regensburg (Germany)
M. Hirmer, Univ. Regensburg (Germany)
F.-X. Schrettenbrunner, Univ. Regensburg (Germany)
D. Weiss, Univ. Regensburg (Germany)
J. Eroms, Univ. Regensburg (Germany)
C. Schüller, Univ. Regensburg (Germany)

Published in SPIE Proceedings Vol. 8456:
Nanophotonic Materials IX
Stefano Cabrini; Taleb Mokari, Editor(s)

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