We report time-resolved (ps) studies of the dynamics of intersubband transitions in p-Si/SiGe multiquantum-well structures in the far-infrared (FIR) regime, ω<ωLO, utilizing the Dutch free electron laser, (entitled FELIX - free electron laser for infrared radiation). The calculated scattering rates for optic and acoustic phonon, and alloy scattering 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 Si 0.7Ge0.3 wells.
|Number of pages||3|
|Journal||Applied Physics Letters|
|Early online date||22 Feb 2002|
|Publication status||Published - 25 Feb 2002|