We report time-resolved (ps) studies of the dynamics of intersubband transitions in p-Si/SiGe multi-quantum well structures in the FIR regime, ℏω < ℏωLO, utilizing the Dutch free electron laser, FELIX. The calculated scattering rates have been included in a rate equation model of the transient FIR intersubband absorption, and show excellent agreement with our degenerate pump-probe spectroscopy measurements where after an initial rise time determined by the resolution of our measurement we determine a decay time of ∼10 ps. This is found to be approximately constant in the temperature range from 4 to 100 K, in good agreement with the predictions of alloy scattering in the Si0.7Ge0.3 wells.
|Number of pages
|Physica E: Low-Dimensional Systems and Nanostructures
|Early online date
|25 Jan 2002
|Published - 1 Mar 2002