Deep level traps and the temperature behavior of the photoluminescence in GaAs/AlGaAs multiple quantum wells grown on off-axis and on-axis substrates

Photoluminescence (PL) spectroscopy from 10 K up to 300 K was performed on ∼50 Å and ∼120 Å GaAs/AlGaAs multiple quantum wells (MQWs) grown on on-axis and off-axis GaAs substrates. An anomalous quenching of the integrated PL in the 80-200 K region was observed for the on-axis substrate-grown samples. X-Ray diffractometry (XRD) showed no significant structural difference between the on- and off-axis samples. Deep-Level Transient Spectroscopy revealed more defects for the on-axis layers. The growth of ∼50 Ǻ MQW on-axis layers appears to be more susceptible to defect formation. The observed PL quenching is attributed to the presence of these traps.