By numerically modeling the spectra, the latter enabled us to clearly identify the emission as the result of intraband recombination. We interpret these results, pure interband absorption, followed by pure intraband emission, as clear evidence for the presence of a sequential photoluminescence process, in which a highly efficient Auger recombination excites energetic electrons into the conduction band, which subsequently recombine via surface-assisted intraband recombination.