  We demonstrate evidence for a radiative recombination channel of dark
excitons in self-assembled quantum dots. This channel is due to a light hole
admixture in the excitonic ground state. Its presence was experimentally
confirmed by a direct observation of the dark exciton photoluminescence from a
cleaved edge of the sample. The polarization resolved measurements revealed
that a photon created from the dark exciton recombination is emitted only in
the direction perpendicular to the growth axis. Strong correlation between the
dark exciton lifetime and the in-plane hole g-factor enabled us to show that
the radiative recombination is a dominant decay channel of the dark excitons in
CdTe/ZnTe quantum dots.
