We present a treatment of intersubband optical absorption in quantum-well structures that takes into account the difference of effective masses in well and bulk materials. We show that this difference itself induces a significant absorption line broadening that may exceed the collision line broadening, depending on the structure parameters. The absorption line profiles and widths versus structure parameters (well thickness and doping level) and temperature dependences are given and discussed.

• Received 27 July 1987

DOI:https://doi.org/10.1103/PhysRevB.37.3097