Thermal conductivity reduction of crystalline silicon by high-pressure torsion

Sivasankaran Harish, Mitsuru Tabara, Yoshifumi Ikoma, Zenji Horita, Yasuyuki Takata, David G. Cahill, Masamichi Kohno

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13 Citations (Scopus)

Abstract

We report a dramatic and irreversible reduction in the lattice thermal conductivity of bulk crystalline silicon when subjected to intense plastic strain under a pressure of 24 GPa using high-pressure torsion (HPT). Thermal conductivity of the HPT-processed samples were measured using picosecond time domain thermoreflectance. Thermal conductivity measurements show that the HPT-processed samples have a lattice thermal conductivity reduction by a factor of approximately 20 (from intrinsic single crystalline value of 142 Wm-1 K-1 to approximately 7.6 Wm-1 K-1). Thermal conductivity reduction in HPT-processed silicon is attributed to the formation of nanograin boundaries and metastable Si-III/XII phases which act as phonon scattering sites, and because of a large density of lattice defects introduced by HPT processing. Annealing the samples at 873 K increases the thermal conductivity due to the reduction in the density of secondary phases and lattice defects.

Original languageEnglish
Article number326
Number of pages5
JournalNanoscale Research Letters
Volume9
Issue number1
DOIs
Publication statusPublished - Jan 1 2014

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics

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