Improvement of photoluminescence and electroluminescence characteristics of MBE-grown In 0.53 Ga 0.47 As/In 0.53 (Ga 0.6 Al 0.4 ) 0.47 As quantum well laser structure with InGaAlAs digital alloys by thermal annealing

We investigated the effect of rapid thermal annealing (RTA) on the photoluminescence (PL) and electroluminescence of the In0.53Ga0.47As/In0.53(Ga0.6Al0.4)0.47As multiple quantum well (MQW) laser structure with InGaAlAs barrier layers provided by the digital-alloy technique. The SiO2- (Si3N4-) capped samples followed by the RTA exhibited a significant improvement of PL intensity without any appreciable shifts in PL peak energy for settings of up to 750 °C (800 °C) for 45 s. This improvement is attributed to the annealing of nonradiative defects in InAlAs layers of digital-alloy InGaAlAs and partially those near the heterointerfaces of the digital-alloy layers. The InGaAs/InGaAlAs MQW laser diodes fabricated on the samples annealed at 850 °C show a hugely improved lasing performance.