Hydrostatic Pressure Dependence of First‐Order Raman Frequencies in Se and Te

Richter, Wolfgang; Renucci, J. B.; Cardona, M.

doi:10.1002/pssb.2220560120

Cited by 69 publications

(19 citation statements)

References 21 publications

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“…The Raman-active phonon modes of Sb 2 Te 3 (space group R-3m) shift upwards with increasing pressure while that of Te shift downwards with increasing pressure. [32,42] Unlike the reported Raman shift caused by the uniform external pressure in all directions, the shift of phonon modes by internal pressure will be preferred directionality according to the heterostructure. The Raman active mode E g 2 corresponds to the (00l) orientation of Sb 2 Te 3 in this paper.…”

Section: Lattice Strain Induced By Crystallization and Growth Of Te Nmentioning

confidence: 79%

Lattice Strain Enhances Thermoelectric Properties in Sb₂Te₃/Te Heterostructure

Chen

et al. 2019

Adv Elect Materials

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κ, κ e , κ L , and T are the Seebeck coefficient, electrical conductivity, total thermal conductivity, electrical thermal conductivity, lattice thermal conductivity, and absolute working temperature, respectively. [1,2] Since α, σ, and κ are strongly coupled with each other, a simple improvement in single parameter usually results in a deterioration of the others. The challenge of realizing superior TE properties lies in the improvement of ZT, that is, simultaneously increasing in power factor (PF = α 2 σ) and suppressing κ. Normally, α enhancement can be achieved by a carrier energy filtering effect, caused by band bending at the nanointerfaces between nanoparticle and TE host materials. [2-4] Meanwhile, reducing κ L by phonon scattering is an effective way to reduce κ while maintaining a high σ. Very recently, lattice strains regulated by annealing time have also been observed for remarkably decreasing κ without affecting the carrier mobility (µ). [3] Sb 2 Te 3 and its derivatives are considered to be one of the best p-type TE materials near room temperature. [5] Compared with its bulk counterparts, nanostructured Sb 2 Te 3 film provides promising possibilities for enhanced TE properties and potential applications in micro/nanoelectromechanical systems (MEMS/NEMS) TE device. [6] Experimentally, Sb 2 Te 3 has been prepared by various approaches such as physical vapor deposition (PVD), solid state reaction, and chemical synthesis method and so on. [1,7,8] The effect of substrate, annealing temperature, and thickness on PF as well as the strain-and grain size-dependent κ in Sb 2 Te 3 films was studied. [9-11] PF can be enhanced by introducing nanoscale metal/semimetals into

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Section: Lattice Strain Induced By Crystallization and Growth Of Te Nmentioning

confidence: 79%

Lattice Strain Enhances Thermoelectric Properties in Sb₂Te₃/Te Heterostructure

Chen

et al. 2019

Adv Elect Materials

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“…I n contrast to the usual behaviour they decrease with decreasing temperature. This might be explained along similar lines as the decreasing phonon frequencies found in some hydrostatic pressure experiments [20]. anisotropic bonding properties is to increase the weak force constant by a large ,percentage, leading to a weakening of the strong bonds.…”

Section: Znfrared Reflectivitymentioning

confidence: 81%

A Raman and far‐infrared investigation of phonons in the rhombohedral V₂–VI₃ compounds Bi₂Te₃, Bi₂Se₃, Sb₂Te₃ and Bi₂(Te_1−xSe_x)₃ (0 < x < 1), (Bi_1−ySb_y)₂Te₃ (0 < y < 1)

Richter

Becker

1977

Physica Status Solidi (b)

Self Cite

543

259

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The Raman-active lattice vibrations of Bi,Se,, Bi,Te,, Sb,Te,, and their solid solutions, whose symmetries correspond to tho R5m space group, are investigated by Raman scattering. Three of the four expected Raman modes, E, and AI,, could be determined. The F I R optical properties of Bi,Te, crystal surfaces of improved quality ( E I I c and E 1 c ) and Bi,Se, ( E _L c ) are re-examined near helium and room temperature with a Fourier spectrometer, allowing a determination of the infrared-active mode frequencies with higher accuracy. The results for Bi,Te, are compared to the predicted frequencies from the lattice dynamical model, given by Jenkins e t al. The frequency shifts of the Raman-active modes in the mixed crystals show single-mode and two-mode behaviour, which is in agreement with simple models for the substitution of antimony and selenium atoms for bismuth and tellurium, respectively, in Bi,Te,.Die Raman-aktiven Gitterschwingungen der Kristalle Bi,Se,, Bi,Te,, Sb,Te, und ihrer Mischkristallreihen mit der Raumgruppe R3m werden durch Raman-Streuung untersucht. Die verschiedenen E,-und Alg-Raman-Moden konnen durch Polarisationsmessangen unterschiedcn werden, wobei drei der vier zu erwartenden Raman-Moden gefunden werden. Die FIR-optischen Eigenschaften von Bi,Te, ( E I j c u n d E 1_ c ) und Bi,Se, ( E _L c ) werden erneut rnit Hilfe eines Fourierspektrometers bei Helium-und Raumtemperatur a n Kristalloberflachen mit besserer Qualitat untersucht, woraus die infrarot-aktiven Eigenfrequenzen rnit hoherer Genauigkeit bestimnit werden konnen. Die Eigenfrequenzen fur Bi,Te, werden mit den Ergebnissen des gitterdynamischen Modells von Jenkins e t al. verglichen. Die Verschiebung der Ramanfrequenzen mit der Mischkristall-Zusammensetzung zeigt Ein-Moden-und Zwei-Moden-Verhalten, die -ausgehend von reinem Bi,Te, -in grober Naherung durch einfache Modelle fur die Substitution von Tellur-durch Selen-Atome bzw. Wismut-durch Antimon-At,ome erklart werden konnen.

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“…The Raman vibrational modes for Se has been assigned in two spectral regions, one is bond-bending (70-150 cm -1 ) and another is bond stretching (200-300 cm -1 ) [17]. The main Raman band at 250 cm -1 can be ascribed to the eight membered Se8 rings [18][19]. The observation of feeble peaks at ~ 112 cm -1 and 369 cm -1 can be ascribed to the bond bending modes of the Se and found to vanish for further composition due [17,20].…”

Section: Raman Analysismentioning

confidence: 99%

Structure and Optical Properties of Polycrystalline InxSb30 – xSe70 (0 ≤ x ≤ 25) Chalcogenide Alloys

Sharma¹,

Sharma²,

Kumar³

et al. 2016

J. Nano- Electron. Phys.

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The spectroscopic studies of various physical properties of glassy and polycrystalline chalcogenide alloys are important due to their importance as active materials in various solid state devices. The composition dependence of these properties are explained on the basis of coordination number, but the splitting of this effect from the nature of additive is imperative for furthering the understanding of these systems. In the present work, the structural and spectroscopic investigations of melt quenched bulk In-Sb-Se chalcogenide alloys have been studied by XRD, RAMAN and optical spectroscopic techniques. The XRD study reveals the polycrystalline nature of the samples. The composition was analysed using the energy dispersive X-ray spectroscopy technique. The XRD study reveals the crystallization of Sb2Se3 and -In2Se3 phases while the increase in the intensity for -In2Se3 phase has been observed with the increase in indium content. The RAMAN spectra also reveal the formation of chalcogenide based Sb and In structural units. The diffused reflectance spectrum was used to calculate the optical absorption in 800-1500 nm spectral region and used to study the composition dependence of the optical gap in these samples. The results have been discussed in conjunction with the heterogeneous phases; density of defect states; electronegativity and average mean bond energy for these polycrystalline alloys.

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Hydrostatic Pressure Dependence of First‐Order Raman Frequencies in Se and Te

Abstract: Measurements of the effcct of hydrostatic pressure on the first order Raman frequencies Show more

Cited by 69 publications

References 21 publications

Lattice Strain Enhances Thermoelectric Properties in Sb₂Te₃/Te Heterostructure

Lattice Strain Enhances Thermoelectric Properties in Sb₂Te₃/Te Heterostructure

A Raman and far‐infrared investigation of phonons in the rhombohedral V₂–VI₃ compounds Bi₂Te₃, Bi₂Se₃, Sb₂Te₃ and Bi₂(Te_1−xSe_x)₃ (0 < x < 1), (Bi_1−ySb_y)₂Te₃ (0 < y < 1)

Structure and Optical Properties of Polycrystalline InxSb30 – xSe70 (0 ≤ x ≤ 25) Chalcogenide Alloys

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Hydrostatic Pressure Dependence of First‐Order Raman Frequencies in Se and Te

Abstract: Measurements of the effcct of hydrostatic pressure on the first order Raman frequencies Show more

Cited by 69 publications

References 21 publications

Lattice Strain Enhances Thermoelectric Properties in Sb2Te3/Te Heterostructure

Lattice Strain Enhances Thermoelectric Properties in Sb2Te3/Te Heterostructure

A Raman and far‐infrared investigation of phonons in the rhombohedral V2–VI3 compounds Bi2Te3, Bi2Se3, Sb2Te3 and Bi2(Te1−xSex)3 (0 < x < 1), (Bi1−ySby)2Te3 (0 < y < 1)

Structure and Optical Properties of Polycrystalline InxSb30 – xSe70 (0 ≤ x ≤ 25) Chalcogenide Alloys

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Lattice Strain Enhances Thermoelectric Properties in Sb₂Te₃/Te Heterostructure

Lattice Strain Enhances Thermoelectric Properties in Sb₂Te₃/Te Heterostructure

A Raman and far‐infrared investigation of phonons in the rhombohedral V₂–VI₃ compounds Bi₂Te₃, Bi₂Se₃, Sb₂Te₃ and Bi₂(Te_1−xSe_x)₃ (0 < x < 1), (Bi_1−ySb_y)₂Te₃ (0 < y < 1)