Thermoelectric properties of In-rich InGaN and InN/InGaN superlattices

Ju, James Zi-Jian; Sun, Bo; Haunschild, Georg; Loitsch, Bernhard; Stoib, Benedikt; Brandt, Martin S.; Stutzmann, M.; Koh, Yee Kan; Koblmüller, Gregor

doi:10.1063/1.4948446

Cited by 28 publications

(10 citation statements)

References 44 publications

(60 reference statements)

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“…III-nitride semiconductors, especially GaN and InN, are promising materials in a wide range of emerging applications, such as power electronics 2 and light-emitting diodes (LEDs) 1 . Efficient thermal management of these high-power-density devices requires detailed understanding of phonon scattering by dislocations, commonly found in III-nitrides due to limitations of current growth techniques 25 . Also, we present a new route to anisotropically direct heat flow via dislocations, which could be used to guide and spread heat in electronic devices 17 .…”

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confidence: 99%

Dislocation-induced thermal transport anisotropy in single-crystal group-III nitride films

Sun¹,

Haunschild²,

Polanco³

et al. 2018

Nature Mater

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Dislocations, one-dimensional lattice imperfections, are common to technologically important materials such as III-V semiconductors 1 , and adversely affect heat dissipation in e.g., nitride-based high-power electronic devices 2 . For decades, conventional models 3-5 based on nonlinear elasticity theory have predicted this thermal resistance is only appreciable when heat flux is perpendicular to the dislocations. However, this dislocation-induced anisotropic thermal transport has yet to be seen experimentally 6-9 . In this study, we measure strong thermal transport anisotropy governed by highly oriented threading dislocation arrays along the cross-plane direction in micron-thick, single-crystal indium nitride (InN) films. We find that the cross-plane thermal conductivity is more than tenfold higher than the in-plane thermal conductivity at 80 K when the dislocation density is on the order of ~3×10 10 cm -2 . This large anisotropy is not predicted by the conventional models 3,4 . With enhanced understanding of dislocation-phonon interactions, our results open new regimes for tailoring anisotropic thermal transport with line defects, and will facilitate novel methods for directed heat dissipation in thermal management of diverse device applications.Over the past decade, accurate experiments 10,11 and novel theoretical methods 12-16 have significantly advanced knowledge of lattice imperfections (point defects, dislocations, grain boundaries, etc.) and how these impede thermal transport in crystals and nanostructures. This in-depth understanding has facilitated better thermal management of electronic and optoelectronic devices 17 , design of novel thermoelectric materials 18 and development of sophisticated technologies such as heat assisted magnetic recording 19 and phononic devices 20 . Unlike other defects, the role of dislocations in thermal resistance is still poorly understood. From the theoretical perspective, predictive first-principles calculations 12,13,16 of phonon scattering by dislocations is still nascent, partly due to the large supercells required for their description.Thus, most of the recent theoretical efforts still rely on conventional nonlinear elasticity models 3-5,8 , pioneered by Klemens in the mid-1950s, to describe dislocation-phonon interactions.According to these conventional theories, phonons are elastically scattered by dislocations via two distinct mechanisms: static scattering 3-5 and dynamic scattering 8,21 . Dynamic scattering occurs when mobile dislocations resonantly absorb an incident phonon, vibrate and re-emit a phonon through the process. To have resonant phonon-dislocation interactions, the phonon wavelengths must be comparable to the distance between two pinning points in the dislocations 7 . Phonons with such characteristically long wavelengths are important for heat conduction only at low temperatures (e.g., <10 K), and thus dynamic scattering is insignificant for heat transport at elevated temperatures 8 . Static scattering, on the other hand, can arise from the cores of ...

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confidence: 99%

Dislocation-induced thermal transport anisotropy in single-crystal group-III nitride films

Sun¹,

Haunschild²,

Polanco³

et al. 2018

Nature Mater

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“…Extrinsic phonon scattering centers, such as atomic intermixing, interface roughness and contamination, would easily scatter phonons and bury the phonon's intrinsic elastic and inelastic transport processes across interfaces 22 . Epitaxial metal/semiconductor interfaces are usually used to study the intrinsic interface phonon transport due to their importance and high quality 6,[22][23][24] . However, previous studies on epitaxial interfaces used typically lacked atomic-level structural details 12,21 with interface roughness and atomic intermixing often ignored, thus only lead to qualitative analysis and limit our understanding of intrinsic phonon transport across interfaces.…”

Section: With Increasing Interface Roughness Inelastic Phonon Transport Rapidly Diminishes Our Results Provide New Insights On Phonon Tramentioning

confidence: 99%

Inelastic phonon transport across atomically sharp metal/semiconductor interfaces

Song

Liu

et al. 2021

Preprint

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Understanding thermal transport across metal/semiconductor interfaces is crucial for heat dissipation of electronics The dominant heat carriers in non-metals, phonons, transport elastically across most interfaces, except for a few extreme cases where the two materials that formed the interface are highly dissimilar with a large difference in Debye temperature. In this work we show that even for two materials with similar Debye temperatures (Al/Si, Al/GaN), a substantial portion of phonons will transport inelastically across their interfaces at high temperatures, significantly enhancing interface thermal conductance. Moreover, we find that interface roughness strongly affects phonon transport process. For atomically sharp interfaces, phonons are allowed to transport inelastically and interface thermal conductance linearly increases at high temperatures. With increasing interface roughness, inelastic phonon transport rapidly diminishes. Our results provide new insights on phonon transport across interfaces and open up opportunities to engineering interface thermal conductance specifically for materials of relevance to microelectronics.

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“…For nanoscale and microscale GaN devices, interfaces play a critical rule in impeding heat dissipation. The thermal boundary resistance (TBR) at interface is equivalent to as large as micrometer-thick heat sink's thermal resistance, and cannot be ignored [18][19][20][21][22]. For example, Ziade et al [23] reported that the thermal boundary conductance (TBC, which is the reciprocal of TBR) at the interface of GaN/SiC was 230 MW•m −2 •K −1 , which is equivalent to the thermal resistance of 1.7-μm-thick SiC.…”

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confidence: 99%

Reduced thermal boundary conductance in GaN-based electronic devices introduced by metal bonding layer

et al. 2021

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Achieving high interface thermal conductance is one of the biggest challenges in the nanoscale heat transport of GaN-based devices such as light emitting diodes (LEDs), and high electron mobility transistors (HEMTs). In this work, we experimentally measured thermal boundary conductance (TBC) at interfaces between GaN and the substrates with AuSn alloy as a commonly-used adhesive layer by time-domain thermoreflectance (TDTR). We find that the TBCs of GaN/Ti/AuSn/Ti/Si, GaN/ Ti/AuSn/Ti/SiC, and GaN/Ti/AuSn/Ti/diamond, are 16.5, 14.8, and 13.2 MW•m -2 •K -1 at room temperature, respectively. Our measured results show that the TBC of GaN/Ti/AuSn/Ti/SiC interface is inferior to the TBC of pristine GaN/SiC interface, due to the large mismatch of phonon modes between AuSn/Ti and substrates, shown as the difference of Debye temperature of two materials. Overall, we measured the TBC at interface between GaN and thermal conductive substrates, and provided a guideline for designing the interface between GaN and substrate at HEMT from a thermal management point of view.

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Thermoelectric properties of In-rich InGaN and InN/InGaN superlattices

Cited by 28 publications

References 44 publications

Dislocation-induced thermal transport anisotropy in single-crystal group-III nitride films

Dislocation-induced thermal transport anisotropy in single-crystal group-III nitride films

Inelastic phonon transport across atomically sharp metal/semiconductor interfaces

Reduced thermal boundary conductance in GaN-based electronic devices introduced by metal bonding layer

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