Investigation of thermal conductivity of semiconducting melts

Regel, A. R.; Смирнов, И. А.; Shadrichev, E. V.

doi:10.1016/0022-3093(72)90146-9

Cited by 14 publications

(4 citation statements)

References 8 publications

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“…10 However, at high temperatures (>700 °C), the increase in κ in bulk RTG SiGe alloys is attributed to the bipolar effect. 10,66 On the other hand in nanostructured samples, the carriers are dominantly scattered by nanoscale defects whereas at higher temperatures these charge carriers are dominantly scattered by acoustic phonons. 17 The κ comprises of contributions from both lattice (κ L ) and electronic (κ e ) parts with κ e being related to σ by the Wiedemann-Franz law, 67 κ e = LσT.…”

Section: Thermal Transportmentioning

confidence: 99%

The role of nanoscale defect features in enhancing the thermoelectric performance of p-type nanostructured SiGe alloys

et al. 2015

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Despite SiGe being one of the most widely studied thermoelectric materials owing to its application in radioisotope thermoelectric generators (RTG), the thermoelectric figure-of merit (ZT) of p-type SiGe is still quite low, resulting in poor device efficiencies. In the present study, we report a substantial enhancement in ZT∼ 1.2 at 900 °C for p-type nanostructured Si80Ge20 alloys by creating several types of defect features within the Si80Ge20 nanostructured matrix in a spectrum of nano to meso-scale dimensions during its nanostructuring, by employing mechanical alloying followed by spark plasma sintering. This enhancement in ZT, which is ∼25% over the existing state-of-the-art value for a p-type nanostructured Si80Ge20 alloy, is primarily due to its ultralow thermal conductivity of ∼2.04 W m(-1) K(-1) at 900 °C, resulting from the scattering of low-to-high wavelength heat-carrying phonons by different types of defect features in a range of nano to meso-scale dimensions in the Si80Ge20 nanostructured matrix. These include point defects, dislocations, isolated amorphous regions, nano-scale grain boundaries and more importantly, the nano to meso-scale residual porosity distributed throughout the Si80Ge20 matrix. These nanoscale multi-dimensional defect features have been characterized by employing scanning and transmission electron microscopy and correlated with the electrical and thermal transport properties, based on which the enhancement of ZT has been discussed.

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Section: Thermal Transportmentioning

confidence: 99%

The role of nanoscale defect features in enhancing the thermoelectric performance of p-type nanostructured SiGe alloys

et al. 2015

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“…The σ of Bi 2 Te 3 is consistently positively correlated with pressure, as shown in figures 6(a) and (d), which is related to the increased carrier mobility at high pressure [51]. The carrier scattering mechanism of semiconductors is generally dominated by acoustic wave scattering from lattice vibrations [52], in which case their carrier mobility (µ) generally versus temperature by µ ∝ T −α ,where α is a positive constant, demonstrates the negative correlation between mobility and temperature. Therefore, according to σ = neµ [53], the flat or slightly increasing trend of σ with temperature in figure 6(a) is due to the increase in carrier concentration (n).…”

Section: Resultsmentioning

confidence: 93%

High-pressure induces topology boosting thermoelectric performance of Bi₂Te₃

Cheng,

Wang,

Lian

et al. 2024

J. Phys.: Condens. Matter

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Decoupling conductivity (σ) and Seebeck coefficient (S) by electronic topological transitions (ETT) under high pressure (2-4 GPa) is a promising method for Bi2Te3 to optimize thermoelectric (TE) performance. However, the S cannot dramatically increase with increasing σ when ETT occurs in Bi2Te3, which impedes optimizing TE performance by utilizing ETT in Bi2Te3. A new strategy of enhanced ETT by combining lattice distortions and high pressure is proposed in this work. The lattice distortions in Bi2Te3 were introduced by high pressure and high temperature (HPHT) treatment to generate surplus dislocations. The in-situ measurements of σ and S at HPHT in Bi2Te3 with lattice distortions show an enhanced ETT effect at 2 GPa, which causes decouple σ and S with an anomalous increase in its |S| about 22 %. The ETT effect causes the figure of merit (ZT) of Bi2Te3 can be improved to 0.275 at 1.50-2.62 GPa, 460 K, it is more than 62 % compared with 0.79 GPa, at 450 K. The excellent TE performance of Bi2Te3 arising from the lattice distortions can result in local non-hydrostatic pressure which enhances ETT under high pressure. This work provides a new strategy to enhance ETT to decouple σ and S, and search for better TE materials from the pressure dimension in the future.

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“…The Wiedemann-Franz law is applied to estimate k e ¼ sLT, where L ¼ 2.44 Â 10 À8 W U K À2 denotes the Lorenz number and s the measured electrical conductivity at a given temperature T. The upturn behavior of k can be attributed to bipolar contribution to the electronic thermal conductivity. Hence, we consider the bipolar contribution of the thermal conductivity k bp , which can be expressed using the following equation 44,45 k bp ¼ 3LsT…”

Section: Resultsmentioning

confidence: 99%

“…The upturn behavior of κ can be attributed to bipolar contribution to the electronic thermal conductivity. Hence, we consider the bipolar contribution of the thermal conductivity κ bp , which can be expressed using the following equation 44,45 where E g is calculated using the Arrhenius relationship. The combined results ( κ e + κ bp ) for electronic contribution to the thermal conductivity are illustrated in Fig.…”

Section: Resultsmentioning

confidence: 99%

Enhanced thermoelectric properties of hydrothermally synthesized Bi_0.88−xZn_xSb_0.12 nanoalloys below the semiconductor–semimetal transition temperature

et al. 2018

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Investigation of thermal conductivity of semiconducting melts

Cited by 14 publications

References 8 publications

The role of nanoscale defect features in enhancing the thermoelectric performance of p-type nanostructured SiGe alloys

The role of nanoscale defect features in enhancing the thermoelectric performance of p-type nanostructured SiGe alloys

High-pressure induces topology boosting thermoelectric performance of Bi₂Te₃

Enhanced thermoelectric properties of hydrothermally synthesized Bi_0.88−xZn_xSb_0.12 nanoalloys below the semiconductor–semimetal transition temperature

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Investigation of thermal conductivity of semiconducting melts

Cited by 14 publications

References 8 publications

The role of nanoscale defect features in enhancing the thermoelectric performance of p-type nanostructured SiGe alloys

The role of nanoscale defect features in enhancing the thermoelectric performance of p-type nanostructured SiGe alloys

High-pressure induces topology boosting thermoelectric performance of Bi2Te3

Enhanced thermoelectric properties of hydrothermally synthesized Bi0.88−xZnxSb0.12 nanoalloys below the semiconductor–semimetal transition temperature

Contact Info

Product

Resources

About

High-pressure induces topology boosting thermoelectric performance of Bi₂Te₃

Enhanced thermoelectric properties of hydrothermally synthesized Bi_0.88−xZn_xSb_0.12 nanoalloys below the semiconductor–semimetal transition temperature