Carrier collection in a semiconductor quantum well

Data are presented showing that a GaAs quantum well, sandwiched between two epitaxial AlxGa1-xAs(x ∼ 0.4) confining layers, loses its effectiveness as a collector of excess carriers and as a source of recombination radiation for well dimensions Lz < 100 A. It is shown that this behavior is expected because of the difficulty in scattering carriers to the bottom of the quantum well as Lz → lp, the path length for scattering (LO phonon).