Exciton Mapping at Subwavelength Scales in Two-Dimensional Materials

Handle URI:
http://hdl.handle.net/10754/575728
Title:
Exciton Mapping at Subwavelength Scales in Two-Dimensional Materials
Authors:
Tizei, Luiz H. G.; Lin, Yung-Chang; Mukai, Masaki; Sawada, Hidetaka; Lu, Ang-Yu; Li, Lain-Jong ( 0000-0002-4059-7783 ) ; Kimoto, Koji; Suenaga, Kazu
Abstract:
Spatially resolved electron-energy-loss spectroscopy (EELS) is performed at diffuse interfaces between MoS2 and MoSe2 single layers. With a monochromated electron source (20 meV) we successfully probe excitons near the interface by obtaining the low loss spectra at the nanometer scale. The exciton maps clearly show variations even with a 10 nm separation between measurements; consequently, the optical band gap can be measured with nanometer-scale resolution, which is 50 times smaller than the wavelength of the emitted photons. By performing core-loss EELS at the same regions, we observe that variations in the excitonic signature follow the chemical composition. The exciton peaks are observed to be broader at interfaces and heterogeneous regions, possibly due to interface roughness and alloying effects. Moreover, we do not observe shifts of the exciton peak across the interface, possibly because the interface width is not much larger than the exciton Bohr radius.
KAUST Department:
Materials Science and Engineering Program; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; Materials Science and Engineering Program
Publisher:
American Physical Society (APS)
Journal:
Physical Review Letters
Issue Date:
Mar-2015
DOI:
10.1103/PhysRevLett.114.107601
Type:
Article
ISSN:
0031-9007; 1079-7114
Sponsors:
The authors would like to thank M. Kociak for fruitful and enlightening discussions. This work is supported by the JST Research Acceleration programme.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorTizei, Luiz H. G.en
dc.contributor.authorLin, Yung-Changen
dc.contributor.authorMukai, Masakien
dc.contributor.authorSawada, Hidetakaen
dc.contributor.authorLu, Ang-Yuen
dc.contributor.authorLi, Lain-Jongen
dc.contributor.authorKimoto, Kojien
dc.contributor.authorSuenaga, Kazuen
dc.date.accessioned2015-08-24T08:36:42Zen
dc.date.available2015-08-24T08:36:42Zen
dc.date.issued2015-03en
dc.identifier.issn0031-9007en
dc.identifier.issn1079-7114en
dc.identifier.doi10.1103/PhysRevLett.114.107601en
dc.identifier.urihttp://hdl.handle.net/10754/575728en
dc.description.abstractSpatially resolved electron-energy-loss spectroscopy (EELS) is performed at diffuse interfaces between MoS2 and MoSe2 single layers. With a monochromated electron source (20 meV) we successfully probe excitons near the interface by obtaining the low loss spectra at the nanometer scale. The exciton maps clearly show variations even with a 10 nm separation between measurements; consequently, the optical band gap can be measured with nanometer-scale resolution, which is 50 times smaller than the wavelength of the emitted photons. By performing core-loss EELS at the same regions, we observe that variations in the excitonic signature follow the chemical composition. The exciton peaks are observed to be broader at interfaces and heterogeneous regions, possibly due to interface roughness and alloying effects. Moreover, we do not observe shifts of the exciton peak across the interface, possibly because the interface width is not much larger than the exciton Bohr radius.en
dc.description.sponsorshipThe authors would like to thank M. Kociak for fruitful and enlightening discussions. This work is supported by the JST Research Acceleration programme.en
dc.publisherAmerican Physical Society (APS)en
dc.titleExciton Mapping at Subwavelength Scales in Two-Dimensional Materialsen
dc.typeArticleen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalPhysical Review Lettersen
dc.contributor.institutionNatl Inst Adv Ind Sci & Technol, Nanotube Res Ctr, Tsukuba, Ibaraki 3058565, Japanen
dc.contributor.institutionJEOL Ltd, Akishima, Tokyo 1968558, Japanen
dc.contributor.institutionNatl Inst Mat Sci, Tsukuba, Ibaraki 3050044, Japanen
kaust.authorLu, Ang-Yuen
kaust.authorLi, Lain-Jongen
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