scholarly journals Photon treatment effect on the surface and figure of merit of thermoelectric material Bi2Te3−xSex

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
E. Belonogov ◽  
A. Grebennikov ◽  
V. Dybov ◽  
S. Kannykin ◽  
A. Kostyuchenko ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Figure Of Merit ◽  
Nanocrystalline Structure ◽  
Laser Flash ◽  
Surface Layers ◽  
Structure Morphology ◽  
Semiconductor Solid Solution ◽  
Subsurface Layers ◽  
Composition Structure

AbstractThe phase composition, structure, morphology, and thermal conductivity of Bi2Te3−xSex-based semiconductor solid solution after photon treatment (PT) were studied by X-ray diffractometry, SEM, TEM, and the laser flash techniques. It was revealed that PT leads to recrystallization of the subsurface layers of the solid solution with the formation of a heterogeneous nanocrystalline structure. The thermoelectric figure of merit of the semiconductor Bi2Te3−xSex (n-type) solid solution increases after PT due to modification of the surface layers. This is due to the decrease of the thermal conductivity of the studied material after PT.

scholarly journals Термоэлектрические свойства нанокомпозитного Bi-=SUB=-0.45-=/SUB=-Sb-=SUB=-1.55-=/SUB=-Te-=SUB=-2.985-=/SUB=- с микрочастицами SiO-=SUB=-2-=/SUB=-

2019 ◽  
Vol 53 (6) ◽  
pp. 751
Author(s):  
А.А. Шабалдин ◽  
П.П. Константинов ◽  
Д.А. Курдюков ◽  
Л.Н. Лукьянова ◽  
А.Ю. Самунин ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Wide Temperature Range ◽  
Figure Of Merit ◽  
Nanostructured Material ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
P Type

AbstractNanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p -type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO_2 microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO_2 addition by almost 50% (at 300 K). When adding SiO_2, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.

High Effective Thermoelectrics Based on the Mg2Si-Mg2Sn Solid Solution

2011 ◽  
Vol 170 ◽  
pp. 286-292 ◽  
Author(s):  
Mikhail I. Fedorov ◽  
Vladimir K. Zaitsev ◽  
Grigory N. Isachenko
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Carrier Concentration ◽  
Figure Of Merit ◽  
Practical Application ◽  
Environment Friendly ◽  
Dimensionless Figure Of Merit ◽  
Solution Energy ◽  
Wide Range ◽  
P Type

The complex study of the thermoelectric properties in solid solutions between compounds Mg2X (X=Si, Ge, Sn) was accomplished. Analysis of the features of band structure, thermal conductivity and electrical properties in the wide range of temperature and carrier concentration has shown that the most effective thermoelectric can be achieved in the Mg2Si-Mg2Sn solid solution. Energy spectrum and carrier concentration optimization, and, also, lattice thermal conductivity minimization allowed to establish the most effective compounds for the thermoelectrics of n- and p- type. Thermoelectrics with the maximum dimensionless figure of merit of more than 1.2 and average ZT0.9 (in the temperature range 300-800K) were obtained with developed synthesis and doping techniques. These materials are cheap, wide spread and environment friendly, have non-toxic initial components. It is very favorable for practical application.

Pseudo-Superlattices of Bi2Te3 Topological Insulator Films with Enhanced Thermoelectric Performance

2011 ◽  
Vol 1344 ◽  
Author(s):  
V. Goyal ◽  
D Teweldebrhan ◽  
A.A. Balandin
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Topological Insulator ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Laser Flash ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
Surface Transport ◽  
Film Thinning

ABSTRACTIt was recently suggested theoretically that atomically thin films of Bi2Te3 topological insulators have strongly enhanced thermoelectric figure of merit. We used the “graphene-like” exfoliation process to obtain Bi2Te3 thin films. The films were stacked and subjected to thermal treatment to fabricate pseudo-superlattices of single crystal Bi2Te3 films. Thermal conductivity of these structures was measured by the “hot disk” and “laser flash” techniques. The room temperature in-plane and cross-plane thermal conductivity of the stacks decreased by a factor of ∼2.4 and 3.5 respectively as compared to that of bulk. The strong decrease of thermal conductivity with preserved electrical properties translates to ∼140-250% increase in the thermoelectric figure if merit. It is expected that the film thinning to few-quintuples, and tuning of the Fermi level can lead to the topological insulator surface transport regime with the theoretically predicted extraordinary thermoelectric efficiency.

Thermoelectric Properties of Hot-Pressed GaN and InN

2003 ◽  
Vol 793 ◽  
Author(s):  
A. Yamamoto ◽  
S. Yamaguchi
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Laser Flash ◽  
Flash Method ◽  
Nitride Semiconductors ◽  
Hot Press ◽  
Press Method ◽  
Increasing Temperature

ABSTRACTAn attempt was made to obtain bulk III-nitride semiconductors such as InN, GaN and InxGa1−xN alloy using hot-press method in order to test their high temperature thermoelectric properties. The Seebeck coefficient and the resistivity were –10μV/K and 1.8×10−6Ωm for InN, and –50μV/K and 1.9×10−4Ωm for GaN at 300K, respectively. Thermal conductivity determined by laser flash method with porosity correction was 17W/mK for InN and 2.6W/mK for GaN. For InN the Seebeck coefficient and the resistivity increased monotonously with increasing temperature, which indicates that InN is a metal or a degenerately doped semiconductor. The power factor and the figure of merit were 2.1 × 10−4W/mK2and 1.5×10−5K−1for InN and 6.9 × 10−5W/mK2and 2.6×10−5K−1for GaN at 650K, respectively.

Application of Norbury Rule to Thermal Conductivity in Intermetallic Compounds

1994 ◽  
Vol 364 ◽  
Author(s):  
Yoshihiro Terada ◽  
Tetsuo Mohri ◽  
Tomoo Suzuki
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Intermetallic Compounds ◽  
Room Temperature ◽  
Laser Flash ◽  
Flash Method ◽  
Horizontal Distance ◽  
Conductivity Data ◽  
Host Metal ◽  
Thermal Conductivity Λ

AbstractThermal conductivity data at room temperature, which are measured by laser-flash method, are presented in B2 aluminides and titanides, and in nickel based L12 compounds. The thermal conductivity λ is changed in the following order of the compounds. λ(NiAl) >λ(CoAl)>λ(FeAl), λ(NiTi)<λ(CoTi)<λ(FeTi), λ(Ni3Al)>λ(Ni3Si) and λ(Ni3Ga)>λ(Ni3Ge). According to Norbury rule originally proposed for the concentration dependence of electrical resistivity, the increasing rate is greater in the solid solution, where the position of solute elements is more remote in horizontal distance from a host metal in the periodic table. It is found that this rule holds for the thermal conductivity measured for the intermetallic compounds with the combination of a series of guest constituents and a fixed host constituent both in the B2 and Ll2 intermetallic compounds.

Thermoelectric Properties of La-doped BaSi2 and (Ba,Sr)Si2 Solid Solutions

2007 ◽  
Vol 1044 ◽  
Author(s):  
Kohsuke Hashimoto ◽  
Ken Kurosaki ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Dimensionless Figure Of Merit ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
La Doped

AbstractWe studied the thermoelectric properties of BaSi2 and SrSi2. The polycrystalline samples were prepared by spark plasma sintering (SPS). The electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) were measured above room temperature. The maximum values of the dimensionless figure of merit (ZT) were 0.01 at 954 K for BaSi2 and 0.09 at 417 K for SrSi2. We tried to enhance the ZT values of BaSi2 and SrSi2 by prepareing and characterizing La-doped BaSi2 and (Ba,Sr)Si2 solid solution.

scholarly journals Thermoelectric properties of Nb-doped Sr1−x (La0.5Na0.5) x TiO3 perovskites

2021 ◽  
Author(s):  
Makoto Tachibana ◽  
Ahmad Rifqi Muchtar ◽  
Takao Mori
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
High Power ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Power Factor ◽  
Nb Doping

Abstract We report the thermal conductivity (κ) of perovskite Sr1−x(La0.5Na0.5)xTiO3 (0 ≤ x ≤ 1) and the thermoelectric properties of Nb-doped samples for x = 0.1 and 0.2. The κ of the solid solution shows a distinct minimum near the cubic-tetragonal phase boundary at x = 0.2, where the value becomes close to the minimum theoretical κ. Nb doping to x = 0.2 retains the high power factor found in Nb-doped SrTiO3, but also raises the κ to result in a thermoelectric figure of merit of 0.24 at 773 K.

Thermoelectric Properties of K2Bi8Se13−xSx Solid Solutions

2005 ◽  
Vol 886 ◽  
Author(s):  
Theodora Kyratsi ◽  
Sangeeta Lal ◽  
Tim Hogan ◽  
Mercouri G. Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
The Other ◽  
Solid Solution Series ◽  
Type Character ◽  
Derivatives Of

AbstractDerivatives of β-K2Bi8Se13 are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. Up to now substitutions on the Bi and alkali metal sites have been studied in order to tune the thermoelectric properties. In this work, the thermoelectric properties of the sulfur-substituted K2Bi8Se13−xSx (0<x<13) are presented with respect to Seebeck coefficient, the electrical and thermal conductivity as a function of temperature. Seebeck coefficient measurements showed the n-type character of all members while electrical conductivity shows higher values compare to the other solid solution series of the same type. The lattice thermal conductivity is affected due to the Se/S disorder. The temperature dependence of the figure-of-merit ZT shows that these materials have potential for high temperatures applications with promising thermoelectric performance.

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