Band-to-band Auger Recombination in Silicon and Germanium

High concentrations of electrons and holes in silicon and germanium have been achieved by optical injection by a giant pulse ruby laser. The kinetics and spectral distribution of the recombination radiation during and after the injection pulse have been analyzed by a theoretical model which takes into account the heating of the sample by the laser pulse as well as the decrease of the band gap which is due to the high carrier concentration. The decay of the recombination radiation signal shows that a third-order recombination process (band-to-band impact or Auger recombination) is predominant at high concentrations. The value of the Auger recombination coefficient γ 3 ≃ 10 -31 - 4 × 10 -30 cm 6 /s is obtained for silicon in the temperature interval 300 K-800 K.