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. © 2014 Harish et al.; licensee Springer.
CITATION STYLE
Harish, S., Tabara, M., Ikoma, Y., Horita, Z., Takata, Y., Cahill, D. G., & Kohno, M. (2014). Thermal conductivity reduction of crystalline silicon by high-pressure torsion. Nanoscale Research Letters, 9(1), 1–5. https://doi.org/10.1186/1556-276X-9-326
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