GaN thermal transport limited by the interplay of dislocations and size effects

H. Li, R. Hanus, C. A. Polanco, A. Zeidler, G. Koblmüller, Y. K. Koh, L. Lindsay

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41 Scopus citations

Abstract

Measurements and first-principles calculations probe the temperature-dependent thermal conductivity (k) of GaN films with large densities of highly oriented dislocations. We demonstrate that phonon-dislocation scattering is weaker than suggested by previous measurements, likely due to sample and experiment size effects. Nonetheless, dislocation-limited k is observed in samples with large dislocation densities and at lower temperatures where k anisotropy is also observed. Combination of experiment and theory give insights into the interplay of thermal resistance mechanisms limiting GaN functionalities and suggest pathways for tuning k via defect engineering.

Original languageEnglish
Article number014313
JournalPhysical Review B
Volume102
Issue number1
DOIs
StatePublished - Jul 1 2020

Funding

Calculations and manuscript development were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Material Sciences and Engineering Division. Computational resources were provided by the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Y.K.K. acknowledges support from the Singapore Ministry of Education Academic Research Fund Tier 1 FRC Project FY2016. R.H. acknowledges the DOE Science Graduate Research Award Program (2018 Solicitation 2).

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