Abstract
From room‐temperature measurements of the photoluminescence decay time, values for the sum of the interface recombination velocities in a series of GaAs/AlGaAs double heterostructures have been obtained. The effects of various combinations of prelayers of GaAs and AlGaAs have been investigated and we show that it is possible to reduce the sum of the interface recombination velocities to as low as 60 cm/s.