Epitaxial Monolayer MoS<sub>2</sub> on Mica with Novel
Photoluminescence
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Abstract
Molybdenum disulfide (MoS<sub>2</sub>) is back in the spotlight
because of the indirect-to-direct bandgap tunability and valley related
physics emerging in the monolayer regime. However, rigorous control
of the monolayer thickness is still a huge challenge for commonly
utilized physical exfoliation and chemical synthesis methods. Herein,
we have successfully grown predominantly monolayer MoS<sub>2</sub> on an inert and nearly lattice-matching mica substrate by using
a low-pressure chemical vapor deposition method. The growth is proposed
to be mediated by an epitaxial mechanism, and the epitaxial monolayer
MoS<sub>2</sub> is intrinsically strained on mica due to a small adlayer-substrate
lattice mismatch (∼2.7%). Photoluminescence (PL) measurements
indicate strong single-exciton emission in as-grown MoS<sub>2</sub> and room-temperature PL helicity (circular polarization ∼0.35)
on transferred samples, providing straightforward proof of the high
quality of the prepared monolayer crystals. The homogeneously strained
high-quality monolayer MoS<sub>2</sub> prepared in this study could
competitively be exploited for a variety of future applications