Structure variation of intersubband electron-acoustic phonon scattering rate in coupled quantum wells

Intersubband electron - acoustic phonon scattering rates are calculated for asymmetric coupled AlGaAs/GaAs quantum wells (QW) at low temperature. Emphasis is placed on the dependence of the scattering rate on the thickness and position of the AlGaAs barrier in the QW. Strong variation of the scattering rate between the second and the first subbands is obtained for small barrier displacement from the center of the QW. These results show that intersubband scattering rates can be engineered to optimize the performances of far-infrared detectors, lasers, and photovoltaic devices. Moreover, this study shines new light on the discrepancy among recent experimental results for these structures.