Radiative versus non-radiative recombination in high-efficiency mid-IR InSb/InAs/In(Ga,Al)As/GaAs metamorphic nanoheterostructures

Abstract

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.