Interface roughness and alloy-disorder scattering contributions to intersubband transition linewidths

We report measurements of intersubband absorption in single semiconductor quantum wells of different well widths and alloy compositions. The well width dependence of the intersubband absorption linewidth is consistent with broadening dominated by interface roughness. The linewidth, however, is found to be relatively unaffected by alloy composition in the quantum well, making alloying an effective tool in the design of quantum well optical devices relying on intersubband transitions. (C) 1996 American Institute of Physics.