Influence of interface phonons on intersubband scattering in asymmetric coupled quantum wells

A theoretical investigation of intersubband transitions in asymmetric coupled GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As quantum wells is presented in order to understand the role of interface phonons on intersubband scattering times estimated from photoluminescence up-conversion. Photoexcited carrier behavior is analyzed in relation to recent measurements and shows time constants for electron relaxation in agreement with experimental data. We show that interface modes are vital to intersubband relaxation in these structures.