Phonon Mean Free Path in Silicon Between 77 and 250°K

Measurement of transmitted phonon drag across 10 ohm cm p-type silicon indicates a phonon mean free path of the relevant thermal phonons which varies from about 80 {μ} at 77^∘{}K to 12 {μ} at 250^∘{}K. The values depend on the method of evaluation. A simplified analysis suggests that below 150^∘{}K the longitudinal acoustic branch of the phonon spectrum is dominant.