High-Temperature Optical Characterization of Transition Metal Dichalcogenides by Piezoreflectance Measurements

2012 ◽  
Vol 194 ◽  
pp. 158-161 ◽  
Author(s):  
Dumitru O. Dumcenco ◽  
Ying Sheng Huang ◽  
Kwong Kau Tiong ◽  
Andrei Colev ◽  
Corneliu Gherman ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Chemical Vapour ◽  
Optical Characterization ◽  
Band Edge ◽  
Transition Metal Dichalcogenide ◽  
Layered Crystals ◽  
Metal Dichalcogenides ◽  
Excitonic Transitions

A systematic optical characterization of transition metal dichalcogenide layered crystals grown by chemical vapour transport method as well as of natural molybdenite were carried out by using piezoreflectance (PzR) measurements. From a detailed lineshape fit of the room-temperature PzR spectra over an energy range from 1.6 to 5.0 eV, the energies of the band-edge excitonic and higher lying interband direct transitions were determined accurately. The possible assignments of the different origins of excitonic transitions are discussed. The near direct band edge A and B excitonic transitions detected in PzR spectra show a linear red-shift with the temperature increasing up to 525 K. The values of temperature-dependent energies of the excitonic transitions A and B are evaluated and discussed.

Hyper–Rayleigh scattering in 2D redox exfoliated semi-metallic ZrTe2 transition metal dichalcogenide

2020 ◽  
Vol 22 (47) ◽  
pp. 27845-27849
Author(s):  
Manoel L. da Silva-Neto ◽  
Renato Barbosa-Silva ◽  
Cid B. de Araújo ◽  
Christiano J. S. de Matos ◽  
Ali M. Jawaid ◽  
...  
Keyword(s):  
Transition Metal ◽  
Rayleigh Scattering ◽  
Transition Metal Dichalcogenides ◽  
Optical Characterization ◽  
Basic Knowledge ◽  
Transition Metal Dichalcogenide ◽  
Fundamental Interest ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

Nonlinear optical characterization of nanostructured layered transition metal dichalcogenides (LTMDs) is of fundamental interest for basic knowledge and applied purposes.

scholarly journals Exciton g-factors in monolayer and bilayer WSe2 from experiment and theory

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan Förste ◽  
Nikita V. Tepliakov ◽  
Stanislav Yu. Kruchinin ◽  
Jessica Lindlau ◽  
Victor Funk ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Layer Transition ◽  
General Terms ◽  
Indirect Excitons ◽  
Metal Dichalcogenides ◽  
Experimental Findings ◽  
Experimental And Theoretical Studies

Abstract The optical properties of monolayer and bilayer transition metal dichalcogenide semiconductors are governed by excitons in different spin and valley configurations, providing versatile aspects for van der Waals heterostructures and devices. Here, we present experimental and theoretical studies of exciton energy splittings in external magnetic field in neutral and charged WSe2 monolayer and bilayer crystals embedded in a field effect device for active doping control. We develop theoretical methods to calculate the exciton g-factors from first principles for all possible spin-valley configurations of excitons in monolayer and bilayer WSe2 including valley-indirect excitons. Our theoretical and experimental findings shed light on some of the characteristic photoluminescence peaks observed for monolayer and bilayer WSe2. In more general terms, the theoretical aspects of our work provide additional means for the characterization of single and few-layer transition metal dichalcogenides, as well as their heterostructures, in the presence of external magnetic fields.

scholarly journals Second-harmonic generation enhancement in monolayer transition-metal dichalcogenides by using an epsilon-near-zero substrate

2021 ◽  
Vol 3 (1) ◽  
pp. 272-278
Author(s):  
Pilar G. Vianna ◽  
Aline dos S. Almeida ◽  
Rodrigo M. Gerosa ◽  
Dario A. Bahamon ◽  
Christiano J. S. de Matos
Keyword(s):  
Dielectric Constant ◽  
Transition Metal ◽  
Harmonic Generation ◽  
Nonlinear Effect ◽  
Second Harmonic ◽  
2D Materials ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Metal Dichalcogenides ◽  
Epsilon Near Zero

The scheme illustrates a monolayer transition-metal dichalcogenide on an epsilon-near-zero substrate. The substrate near-zero dielectric constant is used as the enhancement mechanism to maximize the SHG nonlinear effect on monolayer 2D materials.

Size-dependent phase stability in transition metal dichalcogenide nanoparticles controlled by metal substrates

Nanoscale ◽  
2021 ◽  
Author(s):  
Albert Bruix ◽  
Jeppe Vang Lauritsen ◽  
Bjork Hammer
Keyword(s):  
Transition Metal ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Phase Stability ◽  
Transition Metal Dichalcogenides ◽  
Transition Metal Dichalcogenide ◽  
Metal Substrates ◽  
Size Dependent ◽  
Metal Dichalcogenides

Nanomaterials based on MoS2 and related transition metal dichalcogenides are remarkably versatile; MoS2 nanoparticles are proven catalysts for processes such as hydrodesulphurization and the hydrogen evolution reaction, and transition metal...

Theoretical characterization of the electronic properties of heterogeneous vertical stacks of 2D metal dichalcogenides containing one doped layer

2020 ◽  
Vol 22 (25) ◽  
pp. 14088-14098
Author(s):  
Amine Slassi ◽  
David Cornil ◽  
Jérôme Cornil
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Optoelectronic Devices ◽  
Metal Dichalcogenides ◽  
Theoretical Characterization ◽  
New Generation

The rise of van der Waals hetero-structures based on transition metal dichalcogenides (TMDs) opens the door to a new generation of optoelectronic devices.

scholarly journals Exfoliated transition metal dichalcogenide nanosheets for supercapacitor and sodium ion battery applications

2019 ◽  
Vol 6 (8) ◽  
pp. 190437 ◽  
Author(s):  
Santanu Mukherjee ◽  
Jonathan Turnley ◽  
Elisabeth Mansfield ◽  
Jason Holm ◽  
Davi Soares ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ion ◽  
Coulombic Efficiency ◽  
Transition Metal Dichalcogenides ◽  
Sodium Ion ◽  
Transition Metal Dichalcogenide ◽  
Composite Electrodes ◽  
Metal Dichalcogenides ◽  
Storage Technologies ◽  
Supercapacitor Applications

Growing concerns regarding the safety, flammability and hazards posed by Li-ion systems have led to research on alternative rechargeable metal-ion electrochemical storage technologies. Among the most notable of these are Na-ion supercapacitors and batteries, motivated, in part, by the similar electrochemistry of Li and Na ions. However, sodium ion batteries (SIBs) come with their own set of issues, especially the large size of the Na + ion, its relatively sluggish kinetics and low energy densities. This makes the development of novel materials and appropriate electrode architecture of absolute significance. Transition metal dichalcogenides (TMDs) have attracted a lot of attention in this regard due to their relative ease of exfoliation, diverse morphologies and architectures with superior electronic properties. Here, we study the electrochemical performance of Mo-based two-dimensional (2D) layered TMDs (e.g. MoS 2 , MoSe 2 and MoTe 2 ), exfoliated in a superacid, for battery and supercapacitor applications. The exfoliated TMD flakes were interfaced with reduced graphene oxide (rGO) to be used as composite electrodes. Electron microscopy, elemental mapping and Raman spectra were used to analyse the exfoliated material and confirm the formation of 2D TMD/rGO layer morphology. For supercapacitor applications in aqueous electrolyte, the sulfide-based TMD (MoS 2 ) exhibited the best performance, providing an areal capacitance of 60.25 mF cm −2 . For SIB applications, TMD electrodes exhibited significantly higher charge capacities than the neat rGO electrode. The initial desodiation capacities for the composite electrodes are 468.84 mAh g −1 (1687.82 C g −1 ), 399.10 mAh g −1 (1436.76 C g −1 ) and 387.36 mAh g −1 (1394.49 C g −1 ) for MoS 2 , MoSe 2 and MoTe 2 , respectively. Also, the MoS 2 and MoSe 2 composite electrodes provided a coulombic efficiency of near 100 % after a few initial cycles.

scholarly journals Lineshape characterization of excitons in monolayer WS2 by two-dimensional electronic spectroscopy

2020 ◽  
Vol 2 (6) ◽  
pp. 2333-2338
Author(s):  
Liang Guo ◽  
Chun-An Chen ◽  
Zhuquan Zhang ◽  
Daniele M. Monahan ◽  
Yi-Hsien Lee ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electronic Spectroscopy ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Metal Dichalcogenides

Two-dimensional electronic spectroscopy (2DES) provides dual perspectives for characterizing exciton lineshape in monolayer transition metal dichalcogenides (TMDCs), allowing discrimination of homogeneous and inhomogeneous linewidths.

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