Electron-Phonon Interaction in Lightly and Highly Doped n-Type Germanium
The phonon conductivity of n-type Ge in the low temperature range has been studied by several workers. Bird and Pearlmanl have carried out extensive measurements of n-Ge in the liquid helium range, where they observed resonance dips in the phonon conductivity vs temperature curves at about 0.7°K. Resonance scattering of phonons in the p-type Ge has been observed in several p-type materials and it is believed that the theory of Suzuki and Mikoshiba2 accounts for the observed thermal conductivity as well as its magnetic field dependence. But this is not true for n-type Ge. The theory for n-type Ge has been given by Griffin and Carruthers3, Keyes, and Kwok5. Suzuki and Mikoshiba6 have given complete expressions for the elastic and inelastic relaxation rates for the phonon scattering by neutral donors in the case of light doped semiconductors. These expressions include inelastic scatterings of phonons from both singlet and triplet states, as well as phonon-assisted absorption processes. These expressions are in such a form that they can be easily applied to the analysis of the phonon conductivity results. Suzuki and Mikoshiba6 also attempted to explain the results at temperatures higher than Tr, the temperature which corresponds to the resonance dips in the K vs T curve.
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