Impact of Isotope Doping on Phonon Thermal Transport in Silicon Nanowires

Hattori, Junichi; Uno, Shigeyasu

doi:10.7567/jjap.52.04cn04

Cited by 9 publications

(13 citation statements)

References 36 publications

(125 reference statements)

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“…Interestingly, there have been only a few theoretical studies on the influence of the isotopic content on basic phonon-related properties of Si nanowires (NWs). 14,15 For instance, molecular dynamics (MD) simulations suggested that the thermal conductivity of Si NWs is reduced exponentially by isotopic impurities at room temperature. 14,15 In the MD research, the simulated thermal conductivity of a 28 Si 0.5 29 Si 0.5 NW yields ∼80% of that of isotopically pure 28 Si NW.…”

Section: * S Supporting Informationmentioning

confidence: 99%

“…14,15 For instance, molecular dynamics (MD) simulations suggested that the thermal conductivity of Si NWs is reduced exponentially by isotopic impurities at room temperature. 14,15 In the MD research, the simulated thermal conductivity of a 28 Si 0.5 29 Si 0.5 NW yields ∼80% of that of isotopically pure 28 Si NW. Also for a 28 Si/ 29 Si multilayer NW with a 1.09 nm period, the calculated thermal conductivity was found to be ∼70% of that of isotopically pure 28 Si NW.…”

Section: * S Supporting Informationmentioning

confidence: 99%

“…14 Other calculations demonstrate an improvement of more than 25% in thermoelectric figure of merit of 28 Si 0.5 29 Si 0.5 NWs as compared to a 28 SiNWs. 15 No experiments have, however, been conducted to elucidate these effects. With this perspective, we report in this work the first experimental investigation of the influence of isotope disorder on the phonon behavior in isotopically engineered Si NWs.…”

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confidence: 99%

“…Indeed, conspicuously missing are experimental investigations of the influence of stable isotope impurities on the basic characteristics of nanoscale materials despite the crucial information they could provide concerning their physical properties. Interestingly, there have been only a few theoretical studies on the influence of the isotopic content on basic phonon-related properties of Si nanowires (NWs). , For instance, molecular dynamics (MD) simulations suggested that the thermal conductivity of Si NWs is reduced exponentially by isotopic impurities at room temperature. , In the MD research, the simulated thermal conductivity of a 28 Si 0.5 29 Si 0.5 NW yields ∼80% of that of isotopically pure 28 Si NW. Also for a 28 Si/ 29 Si multilayer NW with a 1.09 nm period, the calculated thermal conductivity was found to be ∼70% of that of isotopically pure 28 Si NW .…”

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confidence: 99%

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Phonon Engineering in Isotopically Disordered Silicon Nanowires

et al. 2015

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The introduction of stable isotopes in the fabrication of semiconductor nanowires provides an additional degree of freedom to manipulate their basic properties, design an entirely new class of devices, and highlight subtle but important nanoscale and quantum phenomena. With this perspective, we report on phonon engineering in metal-catalyzed silicon nanowires with tailor-made isotopic compositions grown using isotopically enriched silane precursors (28)SiH4, (29)SiH4, and (30)SiH4 with purity better than 99.9%. More specifically, isotopically mixed nanowires (28)Si(x)(30)Si(1-x) with a composition close to the highest mass disorder (x ∼ 0.5) were investigated. The effect of mass disorder on the phonon behavior was elucidated and compared to that in isotopically pure (29)Si nanowires having a similar reduced mass. We found that the disorder-induced enhancement in phonon scattering in isotopically mixed nanowires is unexpectedly much more significant than in bulk crystals of close isotopic compositions. This effect is explained by a nonuniform distribution of (28)Si and (30)Si isotopes in the grown isotopically mixed nanowires with local compositions ranging from x = ∼0.25 to 0.70. Moreover, we also observed that upon heating, phonons in (28)Si(x)(30)Si(1-x) nanowires behave remarkably differently from those in (29)Si nanowires suggesting a reduced thermal conductivity induced by mass disorder. Using Raman nanothermometry, we found that the thermal conductivity of isotopically mixed (28)Si(x)(30)Si(1-x) nanowires is ∼30% lower than that of isotopically pure (29)Si nanowires in agreement with theoretical predictions.

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Section: * S Supporting Informationmentioning

confidence: 99%

Section: * S Supporting Informationmentioning

confidence: 99%

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confidence: 99%

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Phonon Engineering in Isotopically Disordered Silicon Nanowires

et al. 2015

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“…Furthermore, a curve of thermal conductivity vs. the concentration of doping isotope atom (x) is exhibited, which shows a similar tendency with Si x Ge 1−x and a plateau at 0.2 <x<0.8 (We will discuss this tendency in the next section). More simulations have been conducted for the isotope effect on thermal conductivity, like the isotopic core-shell Si NWs (Hattori and Uno, 2013) and isotope radial distribution (Royo and Rurali, 2016). The fabrication of Si isotope NWs is demonstrated in Mukherjee et al (2015) using the VLS method and a 30% decrease of thermal conductivity is shown in isotopically mixed 28 Si 30…”

Section: Si Nwsmentioning

confidence: 99%

Si and SiGe Nanowire for Micro-Thermoelectric Generator: A Review of the Current State of the Art

et al. 2021

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In our environment, the large availability of wasted heat has motivated the search for methods to harvest heat. As a reliable way to supply energy, SiGe has been used for thermoelectric generators (TEGs) in space missions for decades. Recently, micro-thermoelectric generators (μTEG) have been shown to be a promising way to supply energy for the Internet of Things (IoT) by using daily waste heat. Combining the predominant CMOS compatibility with high electric conductivity and low thermal conductivity performance, Si nanowire and SiGe nanowire have been a candidate for μTEG. This review gives a comprehensive introduction of the Si, SiGe nanowires, and their possibility for μTEG. The basic thermoelectric principles, materials, structures, fabrication, measurements, and applications are discussed in depth.

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Tuning thermal transport in Si nanowires by isotope engineering

Royo

Rurali

2016

Phys. Chem. Chem. Phys.

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We study thermal transport in isotopically disordered Si nanowires, discussing the feasibility of phonon engineering for thermoelectric applications within these systems. To this purpose, we carry out atomistic molecular dynamics and nonequilibrium Green's function calculations to characterize the dependence of the thermal conductance as a function of the isotope concentration, isotope radial distribution and temperature. We show that a reduction of the conductivity of up to 20% can be achieved with suitable isotope blends at room temperature and approximately 50% at low temperature. Interestingly, precise control of the isotope composition or radial distribution is not needed. An isotope disordered nanowire roughly behaves like a low-pass filter, as isotope impurities are transparent for long wave-length acoustic phonons, while only mid- and high-frequency optical phonons undergo significant scattering.

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Impact of Isotope Doping on Phonon Thermal Transport in Silicon Nanowires

Cited by 9 publications

References 36 publications

Phonon Engineering in Isotopically Disordered Silicon Nanowires

Phonon Engineering in Isotopically Disordered Silicon Nanowires

Si and SiGe Nanowire for Micro-Thermoelectric Generator: A Review of the Current State of the Art

Tuning thermal transport in Si nanowires by isotope engineering

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