Optical detection of misfit dislocation-induced deep levels at InGaAs/GaAs heterojunctions

Using variable-depth luminescence excitation probes, we have observed discrete emission at characteristic energies from deep electronic states associated with misfit dislocations at InGaAs/GaAs interfaces. These states are localized near the buried heterointerface within the InGaAs layer and exhibit only minor variations in energy with composition and strain. The dislocation-induced spectral features appear only in strain-relaxed InGaAs films and are uncorrelated with additional features due to native bulk defects.