Inhomogeneous broadening of intersubband transitions due to nonscreening roughness of heterointerfaces

The shape of the terahertz absorption peak in quantum wells with rough hete rointerfaces is studied. Although the long-range variations of the ground l evel are screened in heavily doped structures, the intersubband in-plane en ergy remains nonuniform due to the second-level variations. The equation fo r intersubband polarization is considered in the resonant approximation, ta king into account the depolarization shift. The line shape of the intersubb and absorption peak is described for the case with long-range variations of heterointerfaces. (C) 2000 American Institute of Physics. [S0021-8979(00)0 2707-9].