THE OPTICAL PROCESSES IN ALINP GAINP/ALINP QUANTUM-WELLS/

The optical processes in AlInP/GaInP/AlInP quantum wells free from lon g-range ordering are examined by photoluminescence (PL), photoluminesc ence excitation (PLE), acid photoreflectance (PR) measurements. The PL method observes lower transition energy than the PLE and the PR metho ds which observe the space-averaged transition energy. This is because PL originates from localized lower-energy states to which an exciton state relaxes. By analyzing these measurements carried on 20- and 60-A ngstrom-wide wells, the reason for this deviation is ascribed to the f luctuation of the transition energy due to the local variation of the well width by one molecular layer. The plausible share of the band off set for the conduction band against the energy gap difference at the G amma point is obtained by comparing the experimentally obtained relati ve position of the energy levels in AlInP barriers and the 20 Angstrom GaInP well with the calculated ones. This is found to be 0.75 (+/-0.0 6). (C) 1996 American Institute of Physics.