Impact of composition of AlGaInAs confining barriers on emission of InAs quantum dots embedded in AlGaAs/GaAs dot-in-a-well heterostructures

The emission of InAs quantum dots (QDs) grown on Al0.30 Ga0.70As/GaAs heterostructures and integrated into additional capping/buffer quantum wells (QW), known as dot-in-a-well (DWELL) structures, has been investigated. Two different AlGaInAs confining barriers (CBs) and buffer layers (BLs) are compared. The first QD structure includes the Al0.30 Ga0.70As CB (#1) and the In0.15Ga0.85As BL. The second QD structure consists of the Al0.40Ga0.45In0.15As CB (#2) and the In0.25Ga0.75As BL. Comparison of photoluminescence (PL) spectra has revealed that the ground state (GS) emission band in the structure #2 with Al0.40Ga0.45In0.15As CB is characterized by the lower peak energy, smaller PL linewidth (more homogeneous QD sizes) and higher GS emission intensity compared to that parameters in the structure #1 with Al0.30 Ga0.70As CB. The smaller potential barriers at the Al0.40Ga0.45In0.15As CB/QD interfaces in #2 lead to faster thermal decrease in the GS PL intensity at high temperatures compared with that in #1. High-resolution X-ray diffraction (HR-XRD) method was used for the study of the QD structures with the aim of monitoring the sizes and compositions of QDs and QWs. Numerical simulation of HR-XRD scans has shown that the material compositions of QDs and QW in #2 with Al0.40Ga0.45In0.15As CB has not changed in the process of QD structure growth at high temperatures compared to those in #1. The obtained results are interesting for further improvement of InAs/GaAs QD structures for telecommunication technology and optoelectronic applications. •The emission of InAs QDs in DWELL structures with confining barriers (CB): Al0.30 Ga0.70As CB or Al0.40 Ga0.45 In0.15 As CB is investigated at T = 10–500K.•HRTEM images and HR-XRD scans of QD structures are controlled and modeled with X'Pert Epitaxy software.•3.With Al0.40Ga0.45 In0.15 As CB, the intensity of InAs QD emission is higher, GS emission peak is 1.28 μm at 300K (closer to 2nd telecommunication window) and smaller GS FWHM.•With Al0.30 Ga0.70As CB, the intensity of InAs QD emission is lower, GS emission peak is 1.18 μm at 300K and bigger GS FWHM.•Smaller barrier energy of Al0.40Ga0.45In0.15As CB leads to faster thermal quenching of QD emission intensity compared to Al0.30 Ga0.70As CB.