Excitonic energy range dielectric function in GaAs/Ga0.7Al0.3As single quantum wells at room temperature

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Abstract
GaAs/Ga0.7Al0.3As single quantum‐well heterostructures,grown by molecular beam epitaxy, are investigated at room temperature using reflectance spectroscopy in the energy range 1.2–3.6 eV. The dielectric function of GaAs in the wells is deduced in the excitonic transition region around the Γ point of the Brillouin zone. The optical constants are determined on the basis of reflectance data using a Kramers–Kronig analysis, followed by an iterative technique of extraction applied to a multilayer scheme for the samples. The optical transitions, accurately located at the peaks of the absorption spectra, are compared to the transition energies calculated using the finite‐square‐well model in the effective‐mass approximation.