Increased Phonon Scattering by Nanograins and Point Defects in Nanostructured Silicon with a Low Concentration of Germanium
Gaohua Zhu,Hohyun Lee,Yucheng Lan,Xiaowei Wang,Giri Joshi,Dezhi Wang,Jian Yang,Daryoosh Vashaee,H. Guilbert,A. Pillitteri,Mildred S. Dresselhaus,Gang Chen,Zhifeng Ren +12 more
TLDR
The mechanism for phonon scattering by nanostructures and by point defects in nano-structured silicon and the silicon germanium (Ge) alloy and their thermoelectric properties are investigated in this article.Abstract:
The mechanism for phonon scattering by nanostructures and by point defects in nanostructured silicon (Si) and the silicon germanium (Ge) alloy and their thermoelectric properties are investigated. We found that the thermal conductivity is reduced by a factor of 10 in nanostructured Si in comparison with bulk crystalline Si. However, nanosize interfaces are not as effective as point defects in scattering phonons with wavelengths shorter than 1 nm. We further found that a $5\text{ }\text{ }\mathrm{at}.\text{ }%$ Ge replacing Si is very efficient in scattering phonons shorter than 1 nm, resulting in a further thermal conductivity reduction by a factor of 2, thereby leading to a thermoelectric figure of merit 0.95 for ${\mathrm{Si}}_{95}{\mathrm{Ge}}_{5}$, similar to that of large grained ${\mathrm{Si}}_{80}{\mathrm{Ge}}_{20}$ alloys.read more
Citations
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High-performance bulk thermoelectrics with all-scale hierarchical architectures
Kanishka Biswas,Jiaqing He,Ivan Blum,Ivan Blum,Chun I. Wu,Timothy P. Hogan,Timothy P. Hogan,David N. Seidman,Vinayak P. Dravid,Mercouri G. Kanatzidis,Mercouri G. Kanatzidis +10 more
TL;DR: It is shown that heat-carrying phonons with long mean free paths can be scattered by controlling and fine-tuning the mesoscale architecture of nanostructured thermoelectric materials, and an increase in ZT beyond the threshold of 2 highlights the role of, and need for, multiscale hierarchical architecture in controlling phonon scattering in bulk thermoeLECTrics.
Journal ArticleDOI
Enhancement of Thermoelectric Figure-of-Merit by a Bulk Nanostructuring Approach
TL;DR: In this paper, the synthesis process and the relationship between the microstructures and the thermoelectric properties of the nanostructured bulk materials with an enhanced ZT value are reviewed.
Journal ArticleDOI
Experimental Studies on Anisotropic Thermoelectric Properties and Structures of n-Type Bi2Te2.7Se0.3
Xiao Yan,Bed Poudel,Yi Ma,Weishu Liu,Giri Joshi,Hui Wang,Yucheng Lan,Dezhi Wang,Gang Chen,Zhifeng Ren +9 more
TL;DR: In this article, the peak dimensionless thermoelectric figure-of-merit (ZT) of Bi2Te3-based n-type single crystals is about 085 in the ab plane at room temperature.
Journal ArticleDOI
Recent advances in thermoelectric materials
Chhatrasal Gayner,Kamal K. Kar +1 more
TL;DR: In this paper, the physical and chemical properties of various thermoelectric materials are reviewed and strategies for improving the performance of materials are proposed, along with an insight into semiconductor physics.
Journal ArticleDOI
High Thermoelectric Performance in PbTe Due to Large Nanoscale Ag2Te Precipitates and La Doping
TL;DR: In this paper, PbTe-based materials with small ( 1.5 at 775 K) were used for waste heat recovery applications, particularly in automobiles, to reduce carbon emissions.
References
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BookDOI
CRC Handbook of Thermoelectrics
TL;DR: In this article, Rowe et al. proposed a method for reducing the thermal conductivity of a thermoelectric generator by reducing the carrier concentration of the generator, which was shown to improve the generator's performance.