Probing the local dielectric function of WS2 on an Au substrate by near field optical microscopy operating in the visible spectral range

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F22%3A00547356" target="_blank" >RIV/61388955:_____/22:00547356 - isvavai.cz</a>

Výsledek na webu

<a href="http://hdl.handle.net/11104/0323598" target="_blank" >http://hdl.handle.net/11104/0323598</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.apsusc.2021.151672" target="_blank" >10.1016/j.apsusc.2021.151672</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Probing the local dielectric function of WS2 on an Au substrate by near field optical microscopy operating in the visible spectral range

Popis výsledku v původním jazyce

The optoelectronic properties of nanoscale systems such as carbon nanotubes (CNTs), graphene nanoribbons and transition metal dichalcogenides (TMDCs) are determined by their dielectric function. This complex, frequency dependent function is affected by excitonic resonances, charge transfer effects, doping, sample stress and strain, and surface roughness. Knowledge of the dielectric function grants access to a material's transmissive and absorptive characteristics. Here we use the dual scanning near field optical microscope (dual s-SNOM) for imaging local dielectric variations and extracting dielectric function values using a pre-established mathematical inversion method. To demonstrate our approach, we studied a monolayer of WS2 on bulk Au and identified two areas with differing levels of charge transfer. The experiments highlight a further advantage of the technique: the dielectric function of contaminated samples can be measured, as dirty areas can be easily identified and excluded for the calculation, being important especially for exfoliated 2D materials (Rodriguez et al., 2021). Our measurements are corroborated by atomic force microscopy (AFM), Kelvin force probe microscopy (KPFM), photoluminescence (PL) intensity mapping, and tip enhanced photoluminescence (TEPL). We extracted local dielectric variations from s-SNOM images and confirmed the reliability of the obtained values with spectroscopic imaging ellipsometry (SIE) measurements.

Název v anglickém jazyce

Probing the local dielectric function of WS2 on an Au substrate by near field optical microscopy operating in the visible spectral range

Popis výsledku anglicky

The optoelectronic properties of nanoscale systems such as carbon nanotubes (CNTs), graphene nanoribbons and transition metal dichalcogenides (TMDCs) are determined by their dielectric function. This complex, frequency dependent function is affected by excitonic resonances, charge transfer effects, doping, sample stress and strain, and surface roughness. Knowledge of the dielectric function grants access to a material's transmissive and absorptive characteristics. Here we use the dual scanning near field optical microscope (dual s-SNOM) for imaging local dielectric variations and extracting dielectric function values using a pre-established mathematical inversion method. To demonstrate our approach, we studied a monolayer of WS2 on bulk Au and identified two areas with differing levels of charge transfer. The experiments highlight a further advantage of the technique: the dielectric function of contaminated samples can be measured, as dirty areas can be easily identified and excluded for the calculation, being important especially for exfoliated 2D materials (Rodriguez et al., 2021). Our measurements are corroborated by atomic force microscopy (AFM), Kelvin force probe microscopy (KPFM), photoluminescence (PL) intensity mapping, and tip enhanced photoluminescence (TEPL). We extracted local dielectric variations from s-SNOM images and confirmed the reliability of the obtained values with spectroscopic imaging ellipsometry (SIE) measurements.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Applied Surface Science

ISSN

0169-4332

e-ISSN

1873-5584

Svazek periodika

574

Číslo periodika v rámci svazku

FEB 2022

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

8

Strana od-do

151672

Kód UT WoS článku

000727808400001

EID výsledku v databázi Scopus

2-s2.0-85117701028