Peak thermal conductivity measurements of boron arsenide crystals

Zhou, Y and Li, C and Koirala, P and Gamage, GA and Wu, H and Li, S and Ravichandran, NK and Lee, H and Dolocan, A and Lv, B and Broido, D and Ren, Z and Shi, L (2022) Peak thermal conductivity measurements of boron arsenide crystals. In: Physical Review Materials, 6 (6).

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Abstract

Recent experiments have validated prior theories of unusual high thermal conductivity (?) in boron arsenide (BAs) and revealed large ? variation associated with extended and point defects in the samples. The peak ? provides valuable insights into the competition between intrinsic phonon-phonon scattering processes and extrinsic boundary and defect scattering processes in BAs. However, prior measurement methods have not been able to measure the peak ? because of fundamental and technical limitations. Here, we report peak ? measurements of BAs crystals synthesized under different conditions with source materials of different purities via a vapor transport method. For three representative samples, the measured ? peak appears at temperatures between 120 and 150 K and varies from 410±60Wm-1K-1 to 830±100Wm-1K-1. The measured thermal conductivities agree with theoretical calculations across the full temperature range. The similar calculated and measured peak temperatures helps to narrow down the boundary scattering mean free path to be around 4 µm in two samples and 5 µm in another, while the variation of the peak magnitude reveals a one-order-of-magnitude difference in the strength of point defect scattering. The phonon-defect scattering behavior correlates well with the measured electronic Raman scattering background, the impurity concentrations revealed by secondary ion mass spectroscopy, and the Hall concentration and mobility of the p-type samples except for an anomalously high hole concentration that appears in one sample, which indicates nonuniform impurity distribution. The observed correlation clarifies the origins of extrinsic phonon scattering mechanisms in BAs crystals.

Item Type:	Journal Article
Publication:	Physical Review Materials
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to the American Physical Society.
Keywords:	Arsenic compounds; Boron; Crystal impurities; Crystals; Hall mobility; Hole concentration; Hole mobility; III-V semiconductors; Phonon scattering; Point defects, Boundary scattering; Defect scattering; High thermal conductivity; Measurement methods; Measurements of; Phonon scattering process; Phonon-phonon scattering; Prior measurement; Scattering process; Thermal conductivity measurements, Phonons
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	14 Jul 2022 10:16
Last Modified:	14 Jul 2022 10:16
URI:	https://eprints.iisc.ac.in/id/eprint/74420

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