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Tightly bound trions in monolayer MoS2.

TitleTightly bound trions in monolayer MoS2.
Publication TypeJournal Article
Year of Publication2013
AuthorsMak, KFai, He, K, Lee, C, Lee, GHyoung, Hone, J, Heinz, TF, Shan, J
JournalNat Mater
Volume12
Issue3
Pagination207-11
Date Published2013 Mar
ISSN1476-1122
Abstract

Two-dimensional (2D) atomic crystals, such as graphene and transition-metal dichalcogenides, have emerged as a new class of materials with remarkable physical properties. In contrast to graphene, monolayer MoS(2) is a non-centrosymmetric material with a direct energy gap. Strong photoluminescence, a current on/off ratio exceeding 10(8) in field-effect transistors, and efficient valley and spin control by optical helicity have recently been demonstrated in this material. Here we report the spectroscopic identification in a monolayer MoS(2) field-effect transistor of tightly bound negative trions, a quasiparticle composed of two electrons and a hole. These quasiparticles, which can be optically created with valley and spin polarized holes, have no analogue in conventional semiconductors. They also possess a large binding energy (~ 20 meV), rendering them significant even at room temperature. Our results open up possibilities both for fundamental studies of many-body interactions and for optoelectronic and valleytronic applications in 2D atomic crystals.

DOI10.1038/nmat3505
Alternate JournalNat Mater
PubMed ID23202371