Electron-Hole Scattering at High Injection-Levels in Germanium

Abstract

THE principal scattering mechanism which determines the mobilities of the charge carriers in pure semiconductors over a wide range of temperature is the interaction with lattice vibrations. According to the calculations of Fletcher¹, interaction between the Coulomb fields of electrons and holes as they drift in opposite directions leads to a progressive reduction in their conductivity mobilities as the injected carrier density increases above 10¹⁶ cm.⁻³ in germanium at room temperature. Experiments in this laboratory have demonstrated this effect, and a value m_nm_p/ (m_n + m_p) = 0.15 m₀ has been obtained for a combined effective mass for electron-hole scattering (m₀ is the mass of an electron in free space).