Auger recombination at the B centre in gallium arsenide

The experimental results of Henry and Lang (1977) for the B centre in GaAs are compared with theoretical calculations of the multiphonon capture rate, the radiative capture rate and the Auger recombination rate, made within the static coupling scheme in an effective phonon energy dipole approximation. It is found that a theoretical fit, fully consistent with the experimental data, is not possible on the basis of the multiphonon capture mechanism alone, in contrast to the work of previous authors, although this remains the dominant mechanism around room temperature and above, where the capture cross section is strongly temperature-dependent. At low temperatures the dominant contribution is that of an Auger process. In particular, a good fit of both the magnitude and the temperature dependence of the cross section is found for an electron concentration of 1016 cm-3, an effective overlap mod FF mod 2 approximately 3*10-3, an effective phonon energy of 0.018 eV and a lattice adjustment energy of 0.238 eV: values which are shown to be in good accord with what little evidence is available.