Spatially resolved values of the Al/Ga interdiffusion coefficient for p-i-n and n-i-p AlGaAs-GaAs device structures were found to be almost identical in magnitude, but varied with position (by a factor of 2) across a 1-thick multiple quantum well active region. These observations contrasted with theoretical predictions, given that the Fermi level to valence-band energy separation changed by 0.7eV across the intrinsic region, and suggested that impurity-free layer disordering did not provide the necessary uniformity in energy shift for photonic integrated circuit fabrication.

S.Seshadri, L.J.Guido, P.Mitev: Applied Physics Letters, 1995, 67[4], 497-9