Transient spectroscopy of InAs quantum dot molecules

Coupled pairs of InAs quantum dots are grown by molecular-beam epitaxy. Structural and optical characterization is done by means of transmission electron microscopy and photoluminescence, respectively. Photoluminescence spectra consist at least of three well-separated optical transitions that are assigned to molecular energy terms and a substantial exciton lifetime increase is observed. Detailed spectral analysis of the transient luminescence behavior indicates intraterm transitions that could be favorably used for the creation of midinfrared light sources. (C) 2004 American Institute of Physics.