On the importance of antimony for temporal evolution of emission from self-assembled (InGa)(AsSb)/GaAs quantum dots on GaP(001)

Understanding the carrier dynamics of nanostructures is the key for development and optimization of novel semiconductor nano-devices. Here, we study the optical properties and carrier dynamics of (InGa)(AsSb)/GaAs/GaP quantum dots (QDs) by means of non-resonant energy and temperature modulated time-resolved photoluminescence. Studying this material system is important in view of the ongoing implementation of such QDs for nano memory devices. Our set of structures contains a single QD layer, QDs overgrown by a GaSb capping layer, and solely a GaAs quantum well, respectively. Theoretical analytical models allow us to discern the common spectral features around the emission energy of 1.8 eV related to GaAs quantum well and GaP substrate. We observe type-I emission from QDs with recombination times between 2 ns and 10 ns, increasing towards lower energies. The distribution suggests the coexistence of momentum direct and indirect QD transitions. Moreover, based on the considerable tunability of the dots depending on Sb incorporation, we suggest their utilization as quantum photonic sources embedded in complementary metal-oxide-semiconductor (CMOS) platforms, since GaP is almost lattice-matched to Si. Finally, our analysis confirms the nature of the pumping power blue-shift of emission originating from the charged-background induced changes of the wavefunction topology.