Low-density (∼10 9 cm −2 ), long-wavelength (more than 1300 nm at room temperature) InAs/GaAs quantum dots (QDs) with only 1.75-mono-layer (ML) InAs deposition were achieved by using a formation-dissolution-regrowth method. Firstly, small high-density InAs QDs were formed at 490 ∘ C, then the substrate temperature was ramped up to 530 ∘ C, and another 0.2 ML InAs was added. After this process, the density of the InAs QDs became much lower, and their size became much larger. The full width at half maximum of the photoluminescence peak of the low density, long-wavelength InAs QDs was as small as 27.5 meV.

Two kinds of InAs/GaAs quantum dot (QD) structures are grown by molecular beam epitaxy in formationdissolution-regrowth method with different in-situ annealing and regrowth processes. The densities and sizes of quantum dots are different for the two samples. The variation tendencies of PL peak energy, integrated intensity, and full width at half maximum versus temperature for the two samples are analyzed, respectively. We find the anomalous temperature dependence of the InAs/GaAs quantum dots and compare it with other previous reports. We propose a new energy band model to explain the phenomenon. We obtain the activation energy of the carrier through the linear fitting of the Arrhenius curve in a high temperature range. It is found that the GaAs barrier layer is the major quenching channel if there is no defect in the material. Otherwise, the defects become the major quenching channel when some defects exist around the QDs.