Optical properties and Raman-active phonon modes of two-dimensional honeycomb Zintl phases

2017 ◽  
Vol 5 (43) ◽  
pp. 11259-11266 ◽  
Author(s):  
M. Q. Arguilla ◽  
N. D. Cultrara ◽  
M. R. Scudder ◽  
S. Jiang ◽  
R. D. Ross ◽  
...  
Keyword(s):  
Optical Properties ◽  
Raman Spectra ◽  
Band Gaps ◽  
Stacking Sequence ◽  
Two Dimensional ◽  
Phonon Modes ◽  
Zintl Phases ◽  
Group 13 ◽  
Raman Active Phonon

We study how structure and stacking sequence influences the Raman spectra and band gaps in layered intermetallic Zintl phases comprised from honeycomb sheets of group 13, 14, and 15 elements.

Synthesis and optical properties of single-crystalline SnS1−xSex nanobelts

2020 ◽  
Vol 35 (4) ◽  
pp. 276-281
Author(s):  
Shengru Wang ◽  
Xiaofang Lai ◽  
Bingsheng Du ◽  
Junhao Ma ◽  
Peihua Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Property ◽  
Doping Concentration ◽  
Band Gaps ◽  
Phonon Modes ◽  
Facile Hydrothermal Method ◽  
One Dimensional ◽  
Optical Band Gaps ◽  
Structure Morphology ◽  
Se Doping

In this work, SnS1−xSex ternary nanobelts were synthesized by a facile hydrothermal method without the assistance of surfactants. The structure, morphology, microstructure, compositions, chemical valences, phonon modes, and optical band gaps of the SnS1−xSex nanobelts were characterized in detail. The results indicate that the SnS1−xSex nanobelts have uniform one-dimensional morphology and are single crystals with high crystallinity. Se is incorporated into the SnS lattice to substitute for S-forming ternary SnS1−xSex alloy. With the increase of Se doping concentration, the optical band gaps of the nanobelts gradually decrease from 1.15 to 1.01 eV, confirming the tunable optical property achieved here.

Probing the impact of magnetic interactions on the lattice dynamics of two-dimensional Ti2X (X = C, N) MXenes

2018 ◽  
Vol 20 (11) ◽  
pp. 7754-7763 ◽  
Author(s):  
Małgorzata Sternik ◽  
Urszula D. Wdowik
Keyword(s):  
Lattice Dynamics ◽  
Magnetic Interactions ◽  
Two Dimensional ◽  
Phonon Modes ◽  
The Impact ◽  
Raman Active Phonon

Magnetic interactions play an important role in the intensities of the Raman-active phonon modes in Ti2X (X = C, N) monolayers.

Structural, Electronic and Optical Properties of Transition Metal Dichalcogenides Layer PtS2 (Se2) for Nano Devices Applications

2021 ◽  
Vol 886 ◽  
pp. 48-56
Author(s):  
Rusul A. Ghazi ◽  
Dhay Ali Sabur ◽  
Ruaa S. Al-Hasnawy ◽  
Haider O. Muhsen ◽  
Bahjat B. Kadhim ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Band Gaps ◽  
Two Dimensional ◽  
Electronic And Optical Properties ◽  
New Class ◽  
Metal Dichalcogenides ◽  
Direct Band ◽  
Indirect Band Gap

Monolayer materials are promising material in applications, such as possess some layers with sturdy in-plane bonds. These materials represents two-dimensional (2D) materials which are possess a vertical weak Van der Waals (VdW) interactions sandwiched among the neighboring sheets. These structures of layers offer the chance to be split to free atomic layers. So new class material with two dimensional transition metal dichalcogenides which includes PtS2 (Se2) have unique geometric structural, electronic and optical properties are studied. It has attracted the attention of many researchers for its extensive applications in (catalysis, sensing, electronics, and optoelectronics devices). It has been disclosed from the outcomes that these monolayers are dynamically stable according to the phonon calculations. Also, the direct band gaps located at K point for MoS2 and MoSe2 are 1.67 eV and 1.484 eV and for PtS2 and PtSe2 located between Γ-M points are 1.887 and 1.66, respectively. Also, the PtS2 have indirect band gap of about 1.775 eV situated at KΓ- ΓM and for PtSe2 is 1.401 eV at Γ- ΓM path. The results show that the maximum absorption coefficients are between 14×104 and 16.4×104 cm-1 for PtS2 and MoSe2, respectively. Besides, the maximum conductivities are between 2.09×101 and 3.65×1015 1/s for PtSe2 and MoS2, and the major values Likewise, the optical properties determined over rang energy 0.30 eV. The work function is equal 6.197eV for PtS2 and 5.628eV for PtSe2. It has been shown by studying photon dispersion of both monolayers that it is stable because it does not contain imaginary frequencies.

Detection of Chemicals in Mixed, Two-Dimensional Raman Spectra

2010 ◽  
Author(s):  
David Gillis ◽  
Jacob Grun ◽  
Jeffrey Bowles
Keyword(s):  
Raman Spectra ◽  
Two Dimensional

scholarly journals Phonons in Short-Period GaN/AlN Superlattices: Group-Theoretical Analysis, Ab initio Calculations, and Raman Spectra

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 286
Author(s):  
Valery Davydov ◽  
Evgenii Roginskii ◽  
Yuri Kitaev ◽  
Alexander Smirnov ◽  
Ilya Eliseyev ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Density Functional ◽  
Structural Characteristics ◽  
Vibrational Modes ◽  
Phonon Modes ◽  
Short Period ◽  
Group Theoretical Analysis

We report the results of experimental and theoretical studies of phonon modes in GaN/AlN superlattices (SLs) with a period of several atomic layers, grown by submonolayer digital plasma-assisted molecular-beam epitaxy, which have a great potential for use in quantum and stress engineering. Using detailed group-theoretical analysis, the genesis of the SL vibrational modes from the modes of bulk AlN and GaN crystals is established. Ab initio calculations in the framework of the density functional theory, aimed at studying the phonon states, are performed for SLs with both equal and unequal layer thicknesses. The frequencies of the vibrational modes are calculated, and atomic displacement patterns are obtained. Raman spectra are calculated and compared with the experimental ones. The results of the ab initio calculations are in good agreement with the experimental Raman spectra and the results of the group-theoretical analysis. As a result of comprehensive studies, the correlations between the parameters of acoustic and optical phonons and the structure of SLs are obtained. This opens up new possibilities for the analysis of the structural characteristics of short-period GaN/AlN SLs using Raman spectroscopy. The results obtained can be used to optimize the growth technologies aimed to form structurally perfect short-period GaN/AlN SLs.

scholarly journals Polymorphic gallium for active resonance tuning in photonic nanostructures: from bulk gallium to two-dimensional (2D) gallenene

Nanophotonics ◽  
2020 ◽  
Vol 9 (14) ◽  
pp. 4233-4252
Author(s):  
Yael Gutiérrez ◽  
Pablo García-Fernández ◽  
Javier Junquera ◽  
April S. Brown ◽  
Fernando Moreno ◽  
...  
Keyword(s):  
Optical Properties ◽  
Room Temperature ◽  
Phase Change Materials ◽  
Two Dimensional ◽  
Active Materials ◽  
Promising Candidate ◽  
Plasmonic Structures ◽  
Resonance Tuning ◽  
The Many ◽  
Optical Behavior

AbstractReconfigurable plasmonics is driving an extensive quest for active materials that can support a controllable modulation of their optical properties for dynamically tunable plasmonic structures. Here, polymorphic gallium (Ga) is demonstrated to be a very promising candidate for adaptive plasmonics and reconfigurable photonics applications. The Ga sp-metal is widely known as a liquid metal at room temperature. In addition to the many other compelling attributes of nanostructured Ga, including minimal oxidation and biocompatibility, its six phases have varying degrees of metallic character, providing a wide gamut of electrical conductivity and optical behavior tunability. Here, the dielectric function of the several Ga phases is introduced and correlated with their respective electronic structures. The key conditions for optimal optical modulation and switching for each Ga phase are evaluated. Additionally, we provide a comparison of Ga with other more common phase-change materials, showing better performance of Ga at optical frequencies. Furthermore, we first report, to the best of our knowledge, the optical properties of liquid Ga in the terahertz (THz) range showing its broad plasmonic tunability from ultraviolet to visible-infrared and down to the THz regime. Finally, we provide both computational and experimental evidence of extension of Ga polymorphism to bidimensional two-dimensional (2D) gallenene, paving the way to new bidimensional reconfigurable plasmonic platforms.

Structural, electronic, and optical properties of two-dimensional hafnium monoxide nanosheets

2021 ◽  
Vol 130 ◽  
pp. 114690
Author(s):  
Xinxin Deng ◽  
Bingcheng Luo ◽  
Zili Zhang ◽  
Changchun Zhao ◽  
Mengjun Shi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Two Dimensional ◽  
Electronic And Optical Properties

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

Auxetic, flexible, and strain-tunable two-dimensional th-AlN for photocatalytic visible light water splitting with anisotropic high carrier mobility

2021 ◽  
Vol 9 (14) ◽  
pp. 4971-4977
Author(s):  
Mehmet Emin Kilic ◽  
Kwang-Ryeol Lee
Keyword(s):  
Optical Properties ◽  
Visible Light ◽  
Water Splitting ◽  
Carrier Mobility ◽  
Two Dimensional ◽  
Light Water ◽  
Photocatalytic Water Splitting ◽  
Electronic And Optical Properties ◽  
High Carrier Mobility ◽  
High Carrier

Tetrahexagonal AlN: a novel two-dimensional family for photocatalytic water splitting with exceptional mechanical, electronic, and optical properties.

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