Determining Bandgaps in the Layered Group-10 2D Transition Metal Dichalcogenide PtSe2
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989100%3A27360%2F24%3A10255792" target="_blank" >RIV/61989100:27360/24:10255792 - isvavai.cz</a>
Result on the web
<a href="https://onlinelibrary.wiley.com/doi/10.1002/adfm.202408982" target="_blank" >https://onlinelibrary.wiley.com/doi/10.1002/adfm.202408982</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1002/adfm.202408982" target="_blank" >10.1002/adfm.202408982</a>
Alternative languages
Result language
angličtina
Original language name
Determining Bandgaps in the Layered Group-10 2D Transition Metal Dichalcogenide PtSe2
Original language description
Unlike traditional group-6 transition metal dichalcogenides (TMDs), group-10 TMDs such as PtSe2 and PdTe2 possess highly tuneable indirect bandgaps, transitioning from semiconducting in the near-infrared to semimetal behavior with a number of monolayers (MLs). This opens up the possibility of TMD-based mid-infrared and terahertz optoelectronics. Despite this large potential, the optical properties of such materials have shown an extremely large disparity between that predicted and measured. For example, simulations show that a few MLs is required for the semiconductor-semimetal transition, whilst tens of MLs is found experimentally. This is a result of widely used optical extrapolation methods to determine bandgaps, such as the Tauc plot approach, that are not adapted here owing to i) nearby direct transitions, ii) the material dimensionality and iii) large changes in the non-parabolic bandstructure with MLs. Here, uniquely combining optical ellipsometry to determine the complex permittivity, terahertz time resolved spectroscopy for the complex conductivity and in-depth density functional theory (DFT) simulations, it is shown that the optical properties and bandstructure can be determined reliably and demonstrate clearly that the semiconductor-semimetal transition occurs for PtSe2 layers ALMOST EQUAL TO5 MLs. The microscopic origins of the observed transitions and the crucial role of the Coulomb interaction for thin semiconducting layers, and that of interlayer van der Waals forces for multilayer semimetallic samples are also demonstrated. This work of combining complimentary experimental techniques and extensive simulations avoids the application of constrained extrapolation methods to determine the optical properties of group-10 TMDs, and will be of importance for future mid-infrared and terahertz applications.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10306 - Optics (including laser optics and quantum optics)
Result continuities
Project
<a href="/en/project/EH22_008%2F0004631" target="_blank" >EH22_008/0004631: Materials and technologies for sustainable development</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2024
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Advanced Functional Materials
ISSN
1616-301X
e-ISSN
1616-3028
Volume of the periodical
Neuveden
Issue of the periodical within the volume
17 October 2024
Country of publishing house
DE - GERMANY
Number of pages
11
Pages from-to
2408982
UT code for WoS article
001338476400001
EID of the result in the Scopus database
2-s2.0-85206468571