Interfacial recombination velocity in GaAlAs/GaAs heterostructures

Abstract

Photoluminescence time-decay measurements on Ga0.5Al0.5As/GaAs double heterostructures were made over a wide range of GaAs active layer thickness and doping levels at room temperature. Observed decay times τ in variously doped GaAs samples range from 10 to 450 nsec. Effects of self-absorption of luminescence and doping level are demonstrated for GaAs layer thickness d≳1 μm. For d<1 μm, the observed decay times are nearly independent of doping level and vary almost linearly with d. The data are interpreted in terms of a small interfacial recombination velocity (Si=450±100 cm/sec) at the Ga0.5Al0.5As/GaAs interface. The value of Si determined here is an average over the doping levels examined.