Carrier storage and capture dynamics in quantum-dot heterostructures

Photoluminescence and time-resolved photoluminescence measurements of charge tunable quantum-dot heterostructures reveal that by appropriate biasing of the device, about 90% of photogenerated holes can be stored at an interface near to the nanostructures and subsequently transferred into the nanostructures in a controlled fashion. The capture dynamics are sensitive to the form of the valence band potential in the layer that caps the Stranski-Krastanow dots. The dependence of the capture rate on applied electric field suggests that the valence band confinement potential is "soft'' in the capping layer, with a spatial extent of around 14 nm. (C) 2003 American Institute of Physics.