Optical cross sections associated with deep levels in semiconductors. II. Comparison of theory with experiment

For pt.I see ibid., vol.13, p.6167 (1980). The authors analyse the numerical results presented in part I of this paper for the electronic contribution to the photoionisation cross sections of deep levels of a 1 (s-like) and t 2 (p-like) symmetry in direct and indirect gap semiconductors. Whereas in part I they were mainly concerned with the technical aspects of their calculation, here they attempt to establish, in simple physical terms, a link with a wide range of experimental data. They consider several specific systems in Si, GaP and GaAs as well as some general properties of optical spectra reported in the literature. They find that the experimental evidence strongly supports the existence of the predicted band structure and defect-related effects influencing the spectral forms. However, a detailed comparison with experiment on a convincing scale has not been achieved. It would appear that the uncertainties in their theoretical predictions are less significant than those concerning the experimental data.