Uniaxial Stress Effect on the Electron Affinity of theD−State in Germanium

Abstract

Long-wavelength (submillimeter plus millimeter) photoconductivity measurements in doped germanium have been performed under uniaxial compressive stress along the [111] crystal direction. The electron affinity estimated from newly observed spectra is smaller than that in a previous measurement without stress and is consistent with the theoretical prediction for the $D^{-}$ state. The larger electron affinity of the $D^{-}$ state without stress is ascribed to a many-valley effect.