Optical detection of the susceptibility tensor in two-dimensional crystals

Xu, Zhemi; Ferraro, Davide; Zaltron, Annamaria; Galvanetto, Nicola; Martucci, Alessandro; Sun, Luzhao; Yang, Pengfei; Zhang, Yanfeng; Wang, Yuechen; Liu, Zhongfan; Elliott, Joshua D.; Marsili, Margherita; Dell’Anna, Luca; Umari, Paolo; Merano, Michele

doi:10.1038/s42005-021-00711-3

Cited by 32 publications

(18 citation statements)

References 45 publications

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“…Therefore, the body resistance of the VFLG was independent of the substrates. Xu et al also reported that the substrate did not alter the intrinsic optical conductivity of a 2D crystal [32]. The field electron emission characterization of the VFLG on Si, stainless-steel and flexible carbon-cloth substrates were measured to further explore the influence of substrates on VFLG.…”

Section: Resultsmentioning

confidence: 99%

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Effects of Substrates on Nucleation, Growth and Electrical Property of Vertical Few-Layer Graphene

et al. 2022

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A key common problem for vertical few-layer graphene (VFLG) applications in electronic devices is the solution to grow on substrates. In this study, four kinds of substrates (silicon, stainless-steel, quartz and carbon-cloth) were examined to understand the mechanism of the nucleation and growth of VFLG by using the inductively-coupled plasma-enhanced chemical vapor deposition (ICPCVD) method. The theoretical and experimental results show that the initial nucleation of VFLG was influenced by the properties of the substrates. Surface energy and catalysis of substrates had a significant effect on controlling nucleation density and nucleation rate of VFLG at the initial growth stage. The quality of the VFLG sheet rarely had a relationship with this kind of substrate and was prone to being influenced by growth conditions. The characterization of conductivity and field emissions for a single VFLG were examined in order to understand the influence of substrates on the electrical property. The results showed that there was little difference in the conductivity of the VFLG sheet grown on the four substrates, while the interfacial contact resistance of VFLG on the four substrates showed a tremendous difference due to the different properties of said substrates. Therefore, the field emission characterization of the VFLG sheet grown on stainless-steel substrate was the best, with the maximum emission current of 35 µA at a 160 V/μm electrostatic field. This finding highlights the controllable interface of between VFLG and substrates as an important issue for electrical application.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Effects of Substrates on Nucleation, Growth and Electrical Property of Vertical Few-Layer Graphene

et al. 2022

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“…Parameters of interest are extracted by a simultaneous fit of the model parameters to the Psi and Delta curves. Although the technique allows for optical characterization of a sample with thickness down to a monolayer, measurements of the anisotropic samples are challenging 36 and require thick samples to assure sufficient light interaction with in-plane and, especially, outof-plane polarization components to sense the anisotropy. That is particularly difficult for samples with a high refractive index what reduces greatly the angle of refraction and thus the amount of the out-of-plane components of the refracted beam in the sample.…”

Section: A Uniaxial Semiconductorsmentioning

confidence: 99%

Optical constants of several multilayer transition metal dichalcogenides measured by spectroscopic ellipsometry in the 300-1700 nm range: high-index, anisotropy, and hyperbolicity

Munkhbat¹,

Wróbel²,

Antosiewicz³

et al. 2022

Preprint

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Transition metal dichalcogenides (TMDs) attract significant attention due to their exceptional optical and excitonic properties. It was understood already in the 1960s, and recently rediscovered, that many TMDs possess high refractive index and optical anisotropy, which make them attractive for nanophotonic applications. However, accurate analysis and predictions of nanooptical phenomena require knowledge of dielectric constants along both in-and out-of-plane directions and over a broad spectral range -information, which is often inaccessible or incomplete. Here, we present an experimental study of optical constants from several exfoliated TMD multilayers obtained using spectroscopic ellipsometry in the broad range of 300-1700 nm. The specific materials studied include semiconducting WS2, WSe2, MoS2, MoSe2, MoTe2, as well as, in-plane anisotropic ReS2, WTe2, and metallic TaS2, TaSe2, and NbSe2. The extracted parameters demonstrate high-index (n up till ≈ 4.84 for MoTe2), significant anisotropy (n − n ⊥ ≈ 1.54 for MoTe2), and low absorption in the near infrared region. Moreover, metallic TMDs show potential for combined plasmonic-dielectric behavior and hyperbolicity, as their plasma frequency occurs at around ∼1000-1300 nm depending on the material. The knowledge of optical constants of these materials opens new experimental and computational possibilities for further development of all-TMD nanophotonics.

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“…Bi

SeO

is a layered material that was grown as a native oxide on the layered Bi

Se [ 41 ]; however, it remains unclear how it would be grown on other materials. Consequently, more research needs to be conducted, and delicate experimental methods should be employed to measure and verify the actual performance of the 2D vdW materials and their optical and dielectric properties [ 43 , 44 , 45 ].…”

Section: Introductionmentioning

confidence: 99%

A First-Principles Study on the Electronic, Thermodynamic and Dielectric Properties of Monolayer Ca(OH)2 and Mg(OH)2

2022

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We perform first-principles calculations to explore the electronic, thermodynamic and dielectric properties of two-dimensional (2D) layered, alkaline-earth hydroxides Ca(OH)2 and Mg(OH)2. We calculate the lattice parameters, exfoliation energies and phonon spectra of monolayers and also investigate the thermal properties of these monolayers, such as the Helmholtz free energy, heat capacity at constant volume and entropy as a function of temperature. We employ Density Functional Perturbation Theory (DFPT) to calculate the in-plane and out-of-plane static dielectric constant of the bulk and monolayer samples. We compute the bandgap and electron affinity values using the HSE06 functional and estimate the leakage current density of transistors with monolayer Ca(OH)2 and Mg(OH)2 as dielectrics when combined with HfS2 and WS2, respectively. Our results show that bilayer Mg(OH)2 (EOT∼0.60 nm) with a lower solubility in water offers higher out-of-plane dielectric constants and lower leakage currents than does bilayer Ca(OH)2 (EOT∼0.56 nm). Additionally, the out-of-plane dielectric constant, leakage current and EOT of Mg(OH)2 outperform bilayer h-BN. We verify the applicability of Anderson’s rule and conclude that bilayers of Ca(OH)2 and Mg(OH)2, respectively, paired with lattice-matched monolayer HfS2 and WS2, are effective structural combinations that could lead to the development of innovative multi-functional Field Effect Transistors (FETs).

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Optical detection of the susceptibility tensor in two-dimensional crystals

Cited by 32 publications

References 45 publications

Effects of Substrates on Nucleation, Growth and Electrical Property of Vertical Few-Layer Graphene

Effects of Substrates on Nucleation, Growth and Electrical Property of Vertical Few-Layer Graphene

Optical constants of several multilayer transition metal dichalcogenides measured by spectroscopic ellipsometry in the 300-1700 nm range: high-index, anisotropy, and hyperbolicity

A First-Principles Study on the Electronic, Thermodynamic and Dielectric Properties of Monolayer Ca(OH)2 and Mg(OH)2

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