In the present paper we study magneto-intersubband oscillations (MISO) in HgTe/Hg1−xCdxTe single quantum well with "inverted" and "normal" spectra and in conventional In1−xGaxAs/In1−yAlyAs quantum wells with normal band ordering. For all the cases when two branches of the spectrum arise due to spin-orbit splitting, the mutual arrangement of the antinodes of the Shubnikov-de Haas oscillations and the maxima of MISO occurs opposite to that observed in double quantum wells and in wide quantum wells with two subbands occupied and does not agree with the theoretical predictions. A "toy" model is supposed that explain qualitatively this unusual result.

In this Letter, we report on the design optimization of metamorphic InSb/InAs/In(Ga,Al)As/GaAs heterostructures with type-II-in-type-I quantum well (QW) active regions, aimed at the enhancement of their room-temperature photoluminescence (PL). The strong influence of the design of the convex-graded metamorphic buffer layer (MBL) and the value of the MBL inverse step in the range from 2 to 14 mol % In on stresses in such heterostructures, as well as their PL intensity, are discussed. The optimized metamorphic In(Sb,As)/In0.63Ga0.37As/In0.75Al0.25As/MBL/GaAs structure with the inverse step of 10 mol % demonstrates 3.2–3.5 µm mid-IR PL intensity quenching from liquid-nitrogen to room temperature by a factor of 12.

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Nanostructures with a submonolayer InSb type-II insertion inside a InAs/InGaAs type-I quantum well (QW) have been grown by molecular beam epitaxy on GaAs (0 0 1) substrates via a convex-graded InAlAs metamorphic buffer layer (MBL). Selection of optimal growth conditions and design of the MBL-virtual substrate system enables one to increase mid-infrared photoluminescence (PL) and internal quantum efficiency (IQE) of the nanoheterostructures. The maximum low temperature IQE of about 90% has been obtained owing to the residual strain engineering which has resulted in both reduction of the extended defect density in the QW, likely responsible for Shockley–Read–Hall non-radiative recombination, and suppression of the Auger recombination channels in the InAs QW and the barriers. Temperature dependence of the integrated PL intensity was analyzed to determine an activation energy of an additional high-temperature non-radiative process (~49 meV) related presumably to hole delocalization through acceptor states in the strained InAs QW.