Deep level transient spectroscopy, photoreflection and time resolved photoluminescence spectra of self-assembled quantum dots

Self-assembled quantum dots (QD) are attracting widespread interest due to the potential they offer in the device application such as low-threshold lasers, detectors and optical memory structures. We report on the electron-filling photoreflectance and photoluminescence investigation in the 1.5-3 eV photon energy range and at temperatures from 10 to 330 K on stacked layers of Si quantum dots. We observed clear and well-resolved structures, which we attribute to the optical response of different QD families. It is shown that Coulomb interaction can account for the observed optical response of QD families with different morphology coexisting in the semiconductor barrier.