IMPURITY-FREE LAYER DISORDERING IN P-I-N AND N-I-P ALGAAS-GAAS MULTIPLE-QUANTUM-WELL DEVICE STRUCTURES - THE FERMI-LEVEL EFFECT REVISITED

Spatially resolved values of the Al-Ga interdiffusion coefficient for p-i-n and n-i-p AlGaAs-GaAs device structures are found to be nearly i dentical in magnitude, but to vary with position by a factor of 2 acro ss a 1 mu m thick multiple quantum well active region. These observati ons are in marked contrast with theoretical predictions given that the Fermi level to valence-band energy separation changes by 0.7 eV acros s the intrinsic region and suggest that impurity-free layer disorderin g does not provide the necessary uniformity in energy shift for photon ic integrated circuit fabrication in its present state of development. (C) 1995 American Institute of Physics.