Dielectric Properties of NbxW1-xSe2 Alloys

Rigosi, Albert F.; Hill, Heather M.; Krylyuk, Sergiy; Nguyen, Nhan V.; Angela, R Hight Walker; Davydov, Albert V.; Newell, David B.

doi:10.6028/jres.124.035

Cited by 4 publications

(3 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…n stands for the relative absorptivity of the N and F material. [35] According to previous work, [59][60][61] the B of our samples is approximately 1 with, however, substantial variation with NbSe 2 thickness and quality. We now make use of Equation ( 2) to investigate the relative importance of the parameters t s , λ N , B and θ i for the d N -dependence of the normalized charge sheet current density I c (Figure 3).…”

Section: Spin-current Modelsupporting

confidence: 64%

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe₂

Nádvorník

Gueckstock

Niu

et al. 2022

Adv Materials Inter

View full text Add to dashboard Cite

Transition‐metal dichalcogenides (TMDCs) are an aspiring class of materials with unique electronic and optical properties and potential applications in spin‐based electronics. Here, terahertz emission spectroscopy is used to study spin‐to‐charge current conversion (S2C) in the TMDC NbSe2 in ultra‐high‐vacuum‐grown F|NbSe2 thin‐film stacks, where F is a layer of ferromagnetic Fe or Ni. Ultrafast laser excitation triggers an ultrafast spin current that is converted into an in‐plane charge current and, thus, a measurable THz electromagnetic pulse. The THz signal amplitude as a function of the NbSe2 thickness shows that the measured signals are fully consistent with an ultrafast optically driven injection of an in‐plane‐polarized spin current into NbSe2. Modeling of the spin‐current dynamics reveals that a sizable fraction of the total S2C originates from the bulk of NbSe2 with the opposite, negative sign of the spin Hall angle as compared to Pt. By a quantitative comparison of the emitted THz radiation from F|NbSe2 to F|Pt reference samples and the results of ab initio calculations, it is estimated that the spin Hall angle of NbSe2 for an in‐plane polarized spin current lies between ‐0.2% and ‐1.1%, while the THz spin‐current relaxation length is of the order of a few nanometers.

show abstract

Section: Spin-current Modelsupporting

confidence: 64%

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe₂

Nádvorník

Gueckstock

Niu

et al. 2022

Adv Materials Inter

View full text Add to dashboard Cite

show abstract

“…[29]. It is observed that the photoluminescence (PL) spectra are visible for the material after 24 h of exposure to air, emphasizing the importance of protection by encapsulation, prompt measurement or the instantaneous placement of crystal samples into an oxygen-free environment as glove-box [30].…”

Section: Photoluminescencementioning

confidence: 99%

NbSe2 Crystals Growth by Bromine Transport

et al. 2023

View full text Add to dashboard Cite

Recently, low-dimensional structures in the form of bulk crystals and nanoflakes have received considerable interest due to their 2D unique functionality and promising applications in electronics, photonics, sensing devices and photovoltaic solar cells. As a result, remarkable efforts and modifications have been made for the synthesis process of crystalline material by the vapor transport technique. Here, an alternative concept of NbSe2 crystal growth by the chemical vapor transport (CVT) technique using bromine as a vapor transport agent is presented and subsequently analyzed by X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS) spectroscopy. X-ray powder diffraction analysis revealed hexagonal 2H-NbSe2 and 4H-NbSe2 phases, and characteristic Raman and XPS spectra typical for crystalline NbSe2 were obtained. The environmental sensitivity of the grown crystals is manifested by luminescence attributed to oxidized Nb at the samples’ surface.

show abstract

“…Many research groups tried to incorporate Nb into WS 2 or WSe 2 to effectively decrease the band gap with p-type doping. − Chemical vapor deposition (CVD) often produces a NbSe 2 phase segregated from the alloy, forming the heterojunction of NbSe 2 –W 1– x Nb x Se 2 ( x = 0.6). , Scanning transmission electron microscopy (STEM) images revealed the anisotropic atomic distribution with clusters or stripes of Nb (∼10%) doped in WS 2 or WSe 2 . ,, Salehi-Khojin’s group predicted theoretically the homogeneous single phase of the W 1– x Nb x Se 2 alloy at 780 K and synthesized it at 1300 K . Researchers have synthesized composition-tuned W 1– x Nb x Se 2 crystals using chemical vapor transport or monolayer films using CVD at 850 °C. , The direct observation of the W 1– x Nb x Se 2 structure at the atomic scale is essential to understanding their properties, but there has been no reported analysis over a wide composition range.…”

Section: Introductionmentioning

confidence: 99%

Full Composition Tuning of W_1–xNb_xSe₂ Alloy Nanosheets to Promote the Electrocatalytic Hydrogen Evolution Reaction

et al. 2022

View full text Add to dashboard Cite

Composition modulation of transition metal dichalcogenides is an effective way to engineer their crystal/electronic structures for expanded applications. Here, fully composition-tuned W1–x Nb x Se2 alloy nanosheets were produced via colloidal synthesis. These nanosheets ultimately exhibited a notable transition between WSe2 and NbSe2 hexagonal phases at x = 0.6. As x approaches 0.6, point doping is converted into cluster doping and eventually separated domains of WSe2 and NbSe2. Extensive density functional theory calculations predicted the composition-dependent crystal structures and phase transitions, consistently with the experiments. The electrocatalytic activity for the hydrogen evolution reaction (HER) in acidic electrolyte was significantly enhanced at x = 0.2, which was linked with the d-band center. The Gibbs free energy for the H adsorption at various basal and edge sites supported the enhanced HER performance of the metallic alloy nanosheets. We suggested that the dispersed doping structures of Nb atoms resulted in the best HER performance. Our findings highlight the significance of composition tuning in enhancing the catalytic activity of alloys.

show abstract

Dielectric Properties of NbxW1-xSe2 Alloys

Cited by 4 publications

References 54 publications

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe₂

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe₂

NbSe2 Crystals Growth by Bromine Transport

Full Composition Tuning of W_1–xNb_xSe₂ Alloy Nanosheets to Promote the Electrocatalytic Hydrogen Evolution Reaction

Contact Info

Product

Resources

About

Dielectric Properties of NbxW1-xSe2 Alloys

Cited by 4 publications

References 54 publications

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe2

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe2

NbSe2 Crystals Growth by Bromine Transport

Full Composition Tuning of W1–xNbxSe2 Alloy Nanosheets to Promote the Electrocatalytic Hydrogen Evolution Reaction

Contact Info

Product

Resources

About

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe₂

Terahertz Spin‐to‐Charge Current Conversion in Stacks of Ferromagnets and the Transition‐Metal Dichalcogenide NbSe₂

Full Composition Tuning of W_1–xNb_xSe₂ Alloy Nanosheets to Promote the Electrocatalytic Hydrogen Evolution Reaction