The thermal diffusivity of pure silicon has been measured from 300 to 1400°K. The specific heat of the same material over the same temperature range has been measured by Dennison. The thermal conductivity was obtained from the product of the thermal diffusivity, specific heat, and density. At 1400°K about two-thirds of the thermal conductivity was caused by lattice vibrations and one-third by bipolar diffusion. Wiedemann-Franz type diffusion accounted for less than one percent of the total thermal conductivity at 1400°K. Thermal transport by direct transmission of radiation appeared to be negligible up to 1400°K. The Grüneisen constant for silicon from these high-temperature thermal conductivity measurements was 1.96, if the Debye temperature is taken as 636°K.

• Received 21 January 1963

DOI:https://doi.org/10.1103/PhysRev.130.1743