English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/235099
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE
Exportar a otros formatos:


Cathodoluminescence in single and multiwall WS2 nanotubes: Evidence for quantum confinement and strain effect

AuthorsGhosh, S.; Brüser, V.; Kaplan-Ashiri, I.; Popovitz-Biro, R.; Peglow, S.; Martínez, José I. ; Alonso, J. A. ; Zak, A.
Transmission electron microscopy
Quantum confinement
Scanning electron microscopy
Plasma processing
Time dependent density functional theory
Issue Date21-Oct-2020
PublisherAmerican Institute of Physics
Abstract[EN] For nanoparticles with sub-10 nm diameter, the electronic bandgap becomes size dependent due to quantum confinement; this, in turn, affects their electro-optical properties. Thereby, MoS2 and WS2 monolayers acquire luminescent capability, due to the confinement-induced indirect-to-direct bandgap transition. Rolling up of individual layers results in single wall inorganic nanotubes (SWINTs). Up to the present study, their luminescence properties were expected to be auspicious but were limited to theoretical investigations only, due to the scarcity of SWINTs and the difficulties in handling them. By optimizing the conditions in the plasma reactor, relatively high yields of WS2 SWINTs 3–7 nm in diameter were obtained in this work, compared to previous reports. A correlative approach, transmission electron microscopy coupled with a scanning electron microscope, was adapted to overcome handling obstacles and for testing individual nanotubes by low-temperature cathodoluminescence. Clear cathodoluminescence spectra were obtained from WS2-SWINTs and compared with those of WS2 multiwall nanotubes and the corresponding bulk material. Uniquely, the optical properties of INTs acquired from cathodoluminescence were governed by the opposite impact from quantum size effect and strain in the bent triple S-W-S layers. The experimental findings were confirmed by the Density Functional and Time-Dependent Density Functional theoretical modeling of monolayer and bilayer nanotubes of different chiralities and diameters. This study provides experimental evidence of the quantum confinement effect in WS2 SWINTs akin to WS2 monolayer. The ability to tune the electronic structure with morphology or number of layers may be exploited toward photoelectrochemical water splitting with WS2 catalysts, devising field effect transistors, photodetectors, and so on.
Publisher version (URL)https://doi.org/10.1063/5.0019913
Appears in Collections:(ICMM) Artículos
Files in This Item:
File Description SizeFormat 
Ghosh_cathodoluminiscence_Appl_Phys_Rev_2020_VS_Pub.pdfArtículo principal-Vs<-publicada5,94 MBAdobe PDFThumbnail
Show full item record
Review this work

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.