Auger decay of X-point excitons in a type II GaAs/AlGaAs superlattice

The origin and characteristics of the cross-interface photoluminescence observed in hydrostatic-pressure-induced, type II GaAs/AlGaAs superlattices is investigated. A low quantum efficiency luminescence feature with an Auger-limited lifetime, as evidenced by the observation of the "hot" Auger electrons recombining across the GaAs direct-gap, was observed. This feature has been found in a set of MOCVD-prepared superlattices, identical, except for the Al-mole-fraction of the barriers. The feature exhibiting Auger recombination is attributed to the recombination of a cross-interface exciton bound to a neutral donor in the AlGaAs. An impurity-bound-exciton seems necessary to explain the over 3-decade purely exponential decays observed in these experiments. © 1988.