Phonon Scattering in Semiconductors From Thermal Conductivity Studies

Abstract

The lattice thermal conductivity of a number of semiconductors including InSb, GaAs, GaSb, CdTe, and CdS has been measured between 1.7 and 300°K. This, together with previous work on Si and Ge, is used to investigate the validity of the relaxation time expressions for scattering of phonons by boundaries, atomic impurities and electrons, and to discuss phonon-phonon interactions and resonance scattering effects. The results indicate that the boundary scattering and isotope scattering relaxation times lead to accurate calculated values of thermal conductivity only when the materials are exceptionally pure. Structure, which has been identified as due to resonance scattering, has been observed in the data for most of the materials. Electron-phonon scattering has been noted in GaSb but the complexity of the problems make the analysis only qualitative. The maximum transverse acoustical phonon frequency may be of more significance than the Debye temperature for thermal conductivity calculations.