The effect of electron–phonon and electron-impurity scattering on the electronic transport properties of silicon/germanium superlattices

Settipalli, Manoj; Proshchenko, Vitaly; Neogi, Sanghamitra

doi:10.1039/d1tc05878a

Cited by 5 publications

(4 citation statements)

References 106 publications

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“…Figure 7 shows electric transport properties of the CeFe In particular, the sample with x = 0.3 had lower mobility when it had similar carrier concentration to that of the sample with x = 0.1, mainly due to the enhancement in the following carrier scatterings in the sample with x = 0.3. These scatterings have a large impact on the electrical transport properties of materials [39], particularly on the carrier mobility: (i) point defects induced by the fluctuations of mass and strain fields because of the differences in the mass and radius between Fe and Ni. The point defects can not only hinder the hot phonons, but also scatter the carriers.…”

Section: Electrical Transport Propertiesmentioning

confidence: 99%

Alloying engineering for thermoelectric performance enhancement in p-type skutterudites with synergistic carrier concentration optimization and thermal conductivity reduction

Liu¹,

Wang²,

Yang³

et al. 2023

Journal of Advanced Ceramics

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The enhancements in thermoelectric (TE) performances of p-type skutterudites are usually limited due to the relatively low Seebeck coefficients owing to the higher carrier concentration and more impurity phases induced by inherent structural instability of a Fe-based skutterudite. As shown in this study, alloying engineering of Ni doping at Fe sites in a p-type CeFe 3.8 Co 0.2 Sb 12 skutterudite can not only reduce the impurity phases with high thermal conductivity but also regulate the carrier concentration, and thus significantly increase the Seebeck coefficient. The thermal conductivity was largely suppressed due to the enhanced point defect phonon scattering and decreased hole concentration. As a result, a TE figure of merit ZT of the CeFe 3.5 Ni 0.3 Co 0.2 Sb 12 sample reached 0.8, which is approximately 50% higher than that of a Ni-free sample. Appropriate Ni doping can maintain a high ZT at a high temperature by controlling the reduction in a band gap. Therefore, a high average ZT close to 0.8 at 650-800 K for CeFe 3.5 Ni 0.3 Co 0.2 Sb 12 was obtained, which was comparable to or even higher than those of the reported Ce-filled Fe-based skutterudites due to the synergistic optimization of electrical and thermal performances. This study provides a strategy to synergistically optimize electrical-thermal performances of the p-type skutterudites by alloying engineering.

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Section: Electrical Transport Propertiesmentioning

confidence: 99%

Alloying engineering for thermoelectric performance enhancement in p-type skutterudites with synergistic carrier concentration optimization and thermal conductivity reduction

Liu¹,

Wang²,

Yang³

et al. 2023

Journal of Advanced Ceramics

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“…Strain plays a strong role in determining superlattice bands [18][19][20] and electronic properties [19,[21][22][23][24]. We include strained superlattices to train the ML models on band splittings due to strain.…”

Section: Forward Learning Modelmentioning

confidence: 99%

Deep Learning Model for Inverse Design of Semiconductor Heterostructures with Desired Electronic Band Structures

Pimachev

Neogi

2023

Preprint

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First-principles modeling techniques have shown remarkable success in predicting electronic band structures of materials. However, the computational costs make it challenging to use them for predicting band structures of semiconductor heterostructures, that show high variability of atomic structures. We propose a machine learning-assisted first-principles framework that bypasses expensive computations and predicts band structures from the knowledge of atomic structural features. Additionally, the framework directly connects modeling results and experimental data. For example, it accepts images obtained with angle-resolved photoemission spectroscopy as input and predicts the corresponding atomic structures. The framework leverages the physical relationship between atomic environments and bands. We demonstrate the framework using silicon/germanium based superlattices and heterostructures. Once trained on silicon-based systems, the framework can even predict band structures of gallium arsenide thin films. The physics-informed framework establishes an approach to expedite the design and discovery of complex materials with desired band structures, going beyond combinatorial approaches.

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“…For example, efforts focused on germanium and silicon alloys to tune between dominant phonon-phonon and phonon-electron scattering suffered from large changes in defect scattering. [18,19] The MX 2 family of materials provides a unique solution to test the role of phonon-electron scattering in electron transport with minimal changes in other material properties. Indeed, these materials are established type-II Weyl semimetals, with relatively large transport mobilities and evidence for a phonon-electron fluid in NbGe 2 .…”

Section: Introductionmentioning

confidence: 99%

“…For example, efforts focused on germanium and silicon alloys to tune between dominant phonon–phonon and phonon–electron scattering suffered from large changes in defect scattering. [ 18,19 ]…”

Section: Introductionmentioning

confidence: 99%

Engineering Anomalously Large Electron Transport in Topological Semimetals

Plisson,

Yao,

Wang

et al. 2024

Advanced Materials

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Anomalous transport of topological semimetals has generated significant interest for applications in optoelectronics, nanoscale devices, and interconnects. Understanding the origin of novel transport is crucial to engineering the desired material properties, yet their orders of magnitude higher transport than single‐particle mobilities remain unexplained. This work demonstrates the dramatic mobility enhancements result from phonons primarily returning momentum to electrons due to phonon‐electron dominating over phonon‐phonon scattering. Proving this idea, proposed by Peierls in 1932, requires tuning electron and phonon dispersions without changing symmetry, topology, or disorder. This is achieved by combining de Haas ‐ van Alphen (dHvA), electron transport, Raman scattering, and first‐principles calculations in the topological semimetals MX2 (M = Nb, Ta and X = Ge, Si). Replacing Ge with Si brings the transport mobilities from an order magnitude larger than single particle ones to nearly balanced. This occurs without changing the crystal structure or topology and with small differences in disorder or Fermi surface. Simultaneously, Raman scattering and first‐principles calculations establish phonon‐electron dominated scattering only in the MGe2 compounds. Thus, this study proves that phonon‐drag is crucial to the transport properties of topological semimetals and provides insight to engineer these materials further.This article is protected by copyright. All rights reserved

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The effect of electron–phonon and electron-impurity scattering on the electronic transport properties of silicon/germanium superlattices

Abstract: Semiconductor superlattices have been extensively investigated for thermoelectric applications, to explore the effects of compositions, interface structures, and lattice strain environments on the reduction of thermal conductivity, and improvement of...

Cited by 5 publications

References 106 publications

Alloying engineering for thermoelectric performance enhancement in p-type skutterudites with synergistic carrier concentration optimization and thermal conductivity reduction

Alloying engineering for thermoelectric performance enhancement in p-type skutterudites with synergistic carrier concentration optimization and thermal conductivity reduction

Deep Learning Model for Inverse Design of Semiconductor Heterostructures with Desired Electronic Band Structures

Engineering Anomalously Large Electron Transport in Topological Semimetals

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