Electron energy loss spectroscopy of excitons in two-dimensional-semiconductors as a function of temperature
Type
ArticleKAUST Department
Material Science and Engineering ProgramPhysical Science and Engineering (PSE) Division
Date
2016-04-21Online Publication Date
2016-04-21Print Publication Date
2016-04-18Permanent link to this record
http://hdl.handle.net/10754/611772
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We have explored the benefits of performing monochromated Electron Energy Loss Spectroscopy(EELS) in samples at cryogenic temperatures. As an example, we have observed the excitonic absorption peaks in single layer Transition Metal Dichalcogenides. These peaks appear separated by small energies due to spin orbit coupling. We have been able to distinguish the split for MoS2 below 300 K and for MoSe2 below 220 K. However, the distinction between peaks is only clear at 150 K. We have measured the change in absorption threshold between 150 K and 770 K for MoS2 and MoSe2. We discuss the effect of carbon and ice contamination in EELSspectra. The increased spectral resolution available made possible with modern monochromators in electron microscopes will require the development of stable sample holders which reaches temperatures far below that of liquid nitrogen.Citation
Electron energy loss spectroscopy of excitons in two-dimensional-semiconductors as a function of temperature 2016, 108 (16):163107 Applied Physics LettersPublisher
AIP PublishingJournal
Applied Physics Lettersae974a485f413a2113503eed53cd6c53
10.1063/1.4947058