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Single- and narrow-line photoluminescence in a boron nitride-supported MoSe 2 /graphene heterostructure
- Source :
- Comptes Rendus. Physique. 22:77-88
- Publication Year :
- 2022
- Publisher :
- Cellule MathDoc/CEDRAM, 2022.
-
Abstract
- Heterostructures made from van der Waals materials provide a template to investigate proximity effects at atomically sharp heterointerfaces. In particular, near-field charge and energy transfer in heterostructures made from semiconducting transition metal dichalcogenides (TMD) have attracted interest to design model 2D "donor-acceptor" systems and new optoelectronic components. Here, using of Raman scattering and photoluminescence spectroscopies, we report a comprehensive characterization of a molybedenum diselenide (MoSe$_2$) monolayer deposited onto hexagonal boron nitride (hBN) and capped by mono- and bilayer graphene. Along with the atomically flat hBN susbstrate, a single graphene epilayer is sufficient to passivate the MoSe$_2$ layer and provides a homogenous environment without the need for an extra capping layer. As a result, we do not observe photo-induced doping in our heterostructure and the MoSe$_2$ excitonic linewidth gets as narrow as 1.6~meV, hence approaching the homogeneous limit. The semi-metallic graphene layer neutralizes the 2D semiconductor and enables picosecond non-radiative energy transfer that quenches radiative recombination from long-lived states. Hence, emission from the neutral band edge exciton largely dominates the photoluminescence spectrum of the MoSe$_2$/graphene heterostructure. Since this exciton has a picosecond radiative lifetime at low temperature, comparable with the energy transfer time, its low-temperature photoluminescence is only quenched by a factor of $3.3 \pm 1$ and $4.4 \pm 1$ in the presence of mono- and bilayer graphene, respectively. Finally, while our bare MoSe$_2$ on hBN exhibits negligible valley polarization at low temperature and under near-resonant excitation, we show that interfacing MoSe$_2$ with graphene yields a single-line emitter with degrees of valley polarization and coherence up to $\sim 15\,\%$.<br />version 3, 5 figures
- Subjects :
- Materials science
Photoluminescence
Exciton
FOS: Physical sciences
General Physics and Astronomy
01 natural sciences
7. Clean energy
010305 fluids & plasmas
law.invention
Condensed Matter::Materials Science
chemistry.chemical_compound
law
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
0103 physical sciences
Monolayer
010306 general physics
Condensed Matter - Materials Science
Condensed Matter - Mesoscale and Nanoscale Physics
business.industry
Graphene
Doping
Materials Science (cond-mat.mtrl-sci)
Heterojunction
Condensed Matter::Mesoscopic Systems and Quantum Hall Effect
3. Good health
chemistry
Boron nitride
Optoelectronics
business
Bilayer graphene
Subjects
Details
- ISSN :
- 18781535
- Volume :
- 22
- Database :
- OpenAIRE
- Journal :
- Comptes Rendus. Physique
- Accession number :
- edsair.doi.dedup.....5cf3623025041225401eff9a11c3c996
- Full Text :
- https://doi.org/10.5802/crphys.58