Cathodoluminescence from interband transitions in germanium (111) and gallium arsenide (100) crystals.

Abstract

The cathodoluminescence spectra in n-type Ge(111) and semi-insulating (SI) GaAs(100) were measured in the range 2.20--5.20 eV. We observed five structures at 3.05, 3.22, 3.60, 3.90, and 4.30 eV in n-type germanium which are assigned to interband transitions. These results are similar to those of previous works on p-type Ge(111). For SI GaAs, the five structures observed at 2.95, 3.26, 3.88, 4.28, and 4.96 eV also indicate electron-hole recombination transitions between bands. All these results agree with the predictions of theoretical calculations. For lightly doped germanium, it is observed that the band structure does not depend on doping type.