  The results of investigation of bulk GaAs photoluminescence are presented
taken from near-surface layers of different thicknesses using for excitation
the light with the wavelengths which are close but some greater than the
excitonic absorption resonances (so-called bulk photoexcitation). Only the
excitonic and band-edge luminescence is seen under the interband excitation,
while under the bulk excitation, the spectra are much more informative. The
interband excited spectra of all the samples investigated in the present work
are practically identical, whereas the bulk excited PL spectra are different
for different samples and excitation depths and provide the information on the
deep-level point defect composition of the bulk materials.
