Photoluminescence Mapping Analysis of In-Plane Ultrahigh-Density InAs/GaAsSb Quantum Dot Layers

In-plane ultrahigh-density InAs quantum dots (QDs) were grown on the GaAsSb/GaAs(001) and were evaluated by using photoluminescence (PL) mapping system. A spatial complementary relationship between PL intensities of ground state (GS)-related crossed transition (CT) and first excited state (ES1)-related CT was observed under 860 nm light excitation. PL intensities of GS(CT) and ES1(CT) were higher than that of GS-related type-II transition, however, the region with high PL intensity of GS(type-II) almost corresponded to the region with low PL intensities of GS(CT) and ES1(CT). From temperature dependence of PL spectrum, it was found that this GS(type-II) transition region was related to the crystal defects in the QD layer.