AlGaInAs capping layer impact on emission and structure of AlGaAs/GaAs quantum wells with InAs quantum dots

Three types of GaAs/Al0.30Ga0.70As quantum wells (QWs) with InAs quantum dots (QDs) cavered by the different capping layers: GaAs (#1), Al0.30Ga0.70As (#2) and Al0.1Ga0.75In0.15As (#3), have been investigated. The photoluminescence (PL), its temperature dependence and high resolution X-ray diffraction (HR-XRD) methods were applied. It is revealed that QD emission in the structure #3 is characterized by the lower PL peak energy, highest PL intensity and smaller half widths of PL bands, in comparison with the QD emissions in #1 and #2. PL temperature dependences have been studied that revealing the QD material composition in #3 is closer to InAs than those in #1 and #2.