Energy level structure and electron relaxation times in InAs/InxGa1-xAs quantum dot-in-a-well structures

Complementary interband and intraband optical spectroscopic techniques are used to investigate the band structure and carrier relaxation times in technologically important InAs/InGaAs/GaAs quantum dot-in-a-well (DWELL) structures. We determine the dot ground to first excited state energies to be 42 meV in the conduction band and 18 meV in the valence band. Using intraband pump-probe experiments, electron relaxation times from the well states to the dot ground state are measured to be similar to 5 ps at 10 K. Our results provide important parameters for the design and simulation of DWELL-based interband lasers and intraband midinfrared photodetectors. (c) 2007 American Institute of Physics.