OPTICALLY INDUCED VARIABILITY OF THE STRAIN-INDUCED ELECTRIC-FIELDS IN (111) GASB-ALSB QUANTUM-WELLS

Electronic Raman scattering and x-ray diffraction measurements on GaSb/AlSb quantum wells grown on (111) and (100) oriented substrates have been performed. A kinematic simulation of the x-ray diffraction intensity profiles has been used to determine the strain in the layers of the multiple quantum wells. Using the piezoelectric tensor of GaSb and the strain estimated from the x-ray measurements, one expects that an electric field of ∼ 60 kV/cm should exist in the GaSb layers of the (111) oriented sample. Intersubband transitions in the conduction band in the (111) and (100) oriented samples exhibit very different energies. A blue shift of the intersubband transition of the (111) oriented sample from that of (100) sample occurs because of the piezoelectrically-generated electric field in the former. The energy of the intersubband transition of the (111) oriented sample is sensitive to optical excitation density. This sensitivity arises because the electron-hole pairs screen the piezoelectrically generated electric field. © 1990.