Abstract
The dielectric response of molecular‐beam epitaxially grown single Al0.3Ga0.7As/GaAs/Al0.3Ga0.7As square quantum wells with thicknesses in the range 14–59 Å is examined via spectroscopic ellipsometry in the energy range 1.6–5.7 eV. Shifts in the E1 transitions are observed and found to be consistent with the shifts calculated within a simple square well model with finite barrier height using appropriate L‐point parameters of the bulk materials.