Abnormal photoluminescence properties of InAs/InAsSb in-plane ultrahigh-density quantum dots

InAs/InAsSb ultrahigh-density quantum dots (UHD QDs) with a density of 1×1012 cm-2 were fabricated using molecular beam epitaxy, and their photoluminescence (PL) properties were characterized. Through temperature dependences of PL energy, intensity and decay time of UHD QDs, it was found that in-plane strong coupling between adjacent QDs of excited and ground states due to homogeneous broadening of QD levels progressed above 60 K and above 100 K, respectively. The findings regarding the strong coupling at ground states were consistent with the temperature dependence of PL minimum energy outlined in Appendix. In addition, abnormal phenomenon in PL full width at half maximum (FWHM) was attributed to the in-plane miniband formation resulting from strong coupling.