Formations of D- Complexes and D- Band in Germanium

Impurity concentration effects on D - states in Sb-doped germanium have been investigated by means of long-wavelength photoconductivity at 0.38 K and 1.46 K. Higher energy shifts of the spectra with increasing the impurity concentration suggest the existence of D - complexes in the samples with Sb-concentrations from 2×10 14 cm -3 to 1×10 16 cm -3 , and [111]-stress effects on the complexes are also studied. A drastic change of the spectral shape at the concentration of 2×10 16 cm -3 in the steps of increasing the concentration is ascribed to the formation of the D - band.