Coherent and Incoherent Impacts of Nanopillars on the Thermal Conductivity in Silicon Nanomembranes

Huang, Xiangping; Ohori, Daisuke; Yanagisawa, Ryoto; Anufriev, Roman; Samukawa, Seiji; Nomura, Masahiro

doi:10.1021/acsami.0c06030

Cited by 12 publications

(13 citation statements)

References 45 publications

(79 reference statements)

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“…Relevant research on semiconductor materials, such as silicon nanowires (NWs) and membranes, carbon nanotubes and graphene nanoribbons, remarkably verify tunable TC arising from the resonant phonon hybridization, especially for the effect on low-frequency phonons. [7][8][9][10][11][12][13][14] In general, all the structures that can produce flat bands in part of or in the entire Brillouin zone can be regarded as resonant structures. Such structures can be formed with confined atom motions or confined phonon propagation in at least one direction.…”

Section: Introductionmentioning

confidence: 99%

Synergistic impeding of phonon transport through resonances and screw dislocations

et al. 2021

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Improving the control of heat flow at the nanoscale is essential for promoting its applications in many fields, such as energy conversion, thermal informatics, and communication technologies. Here we perform a systematic study on the synergistic effect of screw dislocations and surface resonators on thermal transport of Si nanowires and the corresponding mechanisms based on molecular dynamics simulations. We uncover that screw dislocations reduce the thermal conductivity by enhancing the anharmonicity of nanowires due to the non-homogeneous stress field. For resonant structures, we demonstrate that the suppression of relaxation time is the main mechanism for thermal conductivity reduction. The suppression of relaxation time by more than two orders of magnitude below 4 THz dramatically reduces the resonant structure thermal conductivity, while the previously proposed group velocity reduction mechanism can only impede phonon transport beyond 4 THz slightly. By comparing the mechanisms produced by dislocations and resonators, we find that the resonators have a stronger effect over screw dislocations in impeding the phonon transport at low-frequencies while it becomes opposite at high-frequencies. As a result, they can be combined together to manipulate phonon transport synergistically at all frequencies. Our findings not only provide new insights on the mechanisms of thermal conductivity engineering by screw dislocations and surface resonators, but also illustrate a new paradigm for ultralow thermal conductivity design through the tailoring of the entire frequency range of phonon transport.

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Section: Introductionmentioning

confidence: 99%

Synergistic impeding of phonon transport through resonances and screw dislocations

et al. 2021

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“…Recent thermal transport studies have shown that the in-plane thermal conductivity of silicon and its temperature dependence can be effectively reduced and tuned by patterning periodic arrays of holes [24][25][26] or arrays of pillars [27][28][29]. In silicon membranes with patterned arrays of holes (see Figure 1a-d) a strong reduction of~90% of the thermal conductivity was found compared to unpatterned Si membranes of equal thickness.…”

Section: Membrane-based Structuresmentioning

confidence: 99%

“…The authors attributed this behavior to the increased phonon scattering at the pillar/beam interface due to the intermixing of aluminum and silicon atoms. The same group later fabricated nanopillars on suspended silicon membranes and investigated the impact of nanopillars on the thermal conductivity at low temperatures (4-300 K) [29]. They found the thermal conductivity reduction caused by the nanopillars to be approximately~16%, which was attributed mainly to incoherent phonon boundary scattering.…”

Section: Membrane-based Structuresmentioning

confidence: 99%

“…More recent experimental studies demonstrated that manipulation of crystal phase, isotope composition and mass disorder are effective ways to control heat transport in silicon NWs. For instance, Mukherjee et al showed that isotopically mixed metal-catalyzed 28 Si x 30 Si 1−x NWs exhibit enhanced phonon scattering and approximately 30% decreased thermal conductivity induced by mass disorder in comparison with isotopically pure 29 Si NWs [57]. Figure 2c shows the measured power density as a function of the laser heating for the two types of NWs, which was used together with a model to extract the local temperature and thermal conductivity of the NWs.…”

Section: Nanowiresmentioning

confidence: 99%

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Heat Transport Control and Thermal Characterization of Low-Dimensional Materials: A Review

et al. 2021

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Heat dissipation and thermal management are central challenges in various areas of science and technology and are critical issues for the majority of nanoelectronic devices. In this review, we focus on experimental advances in thermal characterization and phonon engineering that have drastically increased the understanding of heat transport and demonstrated efficient ways to control heat propagation in nanomaterials. We summarize the latest device-relevant methodologies of phonon engineering in semiconductor nanostructures and 2D materials, including graphene and transition metal dichalcogenides. Then, we review recent advances in thermal characterization techniques, and discuss their main challenges and limitations.

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“…Recently, another group also tested the predicted behavior but reached to a different conclusion. [95] They fabricated nanopillars on suspended silicon membranes using damageless neutralbeam etching and investigated the impact of nanopillars on the thermal conductivity of the membranes in the 4-300 K range. They found that thermal conductivity reduction caused by the nanopillars does not exceed 16%, which is much weaker than that predicted by the theoretical works.…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

Thermoelectric Metamaterials: Nano‐Waveguides for Thermoelectric Energy Conversion and Heat Management at the Nanoscale

Zianni

2021

Adv Elect Materials

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are heterostructures, electronic and phononic superlattices that have been extensively studied since their discovery nearly 100 years ago. [2][3][4][5][6][7][8][9] Electrons and phonons in geometry-modulated nanostructures, nano-waveguides (nWVGs), have attracted extended research interest since the 1980s. [10][11][12][13][14] In 2010, we proposed nWVGs for thermoelectric efficiency enhancement by geometrical control of electron and phonon properties. [15][16][17] Thermoelectric (TE) energy conversion could ideally serve the need of our society for low-cost green energy production, reduction of CO 2 emissions and waste-heat recycling. Low efficiencies of traditional thermoelectric materials prohibited for long widespread thermoelectric applications. In the last 20 years, the efforts of the thermoelectric community concentrated to alternative approaches, such as using low-dimensional and nanostructured materials, to enhance the TE efficiency. Much progress has been achieved and research is continuing along these lines. Currently, another dimension has been added by that thermoelectric materials could power the Internet of things (IoT). [18] Already-achieved record efficiencies should be sufficient for this purpose. Nevertheless, traditional thermoelectric materials are not suitable for integration into the microelectronics industrial processes. Novel strategies to enhance the TE efficiency of technologically important materials are of predominant importance and interest. Thermoelectric metamaterials (THEMMs), nWVGs with enhanced TE properties, can contribute to this task. Their operation is based on the same principles as low-dimensional and nanostructured materials.The discovery of low-dimensional materials revolutionized science and technology provide the fascinating ability to engineer the energy bandstructure and properties of matter with superlattices of different materials. [19][20][21] Superlattices made of low-dimensional constituent materials exhibited improved properties and novel functionalities due to quantum confinement. Shrinking dimensions to the nanoscale and forming low-dimensional nanostructures and nanocomposite materials opened-up new horizons in science and led to the era of nanotechnology.Low-dimensional materials have one or more dimensions small enough (typically in the nanometric range) so that carriers The idea of using metamaterials for thermoelectrics was proposed 10 years ago. Enhanced thermoelectric effects and decreased thermal conduction are theoretically demonstrated due to modification of electrons and phonons by quantum interference between propagating and scattered waves at geometrical discontinuities. These structures are now considered promising for breakthrough in thermoelectric energy conversion and heat management at the nanoscale. They could ideally power the Internet of things. This review is devoted to electron and phonon transport properties of thermoelectric metamaterials in the quantum confinement regime. Enhanced thermoelectric effects and decreased thermal conductiv...

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Coherent and Incoherent Impacts of Nanopillars on the Thermal Conductivity in Silicon Nanomembranes

Cited by 12 publications

References 45 publications

Synergistic impeding of phonon transport through resonances and screw dislocations

Synergistic impeding of phonon transport through resonances and screw dislocations

Heat Transport Control and Thermal Characterization of Low-Dimensional Materials: A Review

Thermoelectric Metamaterials: Nano‐Waveguides for Thermoelectric Energy Conversion and Heat Management at the Nanoscale

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