The impact of monolayer coverage, barrier thickness and growth rate on the thermal stability of photoluminescence of coupled InAs/GaAs quantum dot hetero-structure with quaternary capping of InAlGaAs

The self-assembled InAs/GaAs MQDs are widely investigated for their potential application in optoelectronic devices like lasers and photovoltaics. We have explored the effect of QD growth rate and structural parameters like capping layer thickness on the morphology and optical properties of the MQD heterostructures overgrown with a combination capping of InAlGaAs and GaAs. The growth rate of the seed layers in the MQD samples is also varied to investigate its effect in the vertical stacking of the islands. The change in the morphology and the optical properties of the samples due to variation in growth and structural parameters are explained by the presence of strain in the QD structures, which arises due to lattice mismatch.

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► Coupled InAs/GaAs MQDs with (In0.21Al0.21Ga0.58As + GaAs) caps are considered.
► Monolayer coverage, barrier thickness and growth rate of the dots are the factors.
► PL peaks for the samples are within 1.1–1.3 μm; significant for IBSCs and lasers.
► NPTP (non-resonant multi-phonon assisted tunneling process) effect on FWHM of PL.