Quantum well (QW) structures of AlxGa1-xAs/GaAs were characterized by photoluminescence technique as a function of the temperature between 10 and 300 K. The structures were grown on a 500 nm thick GaAs buffer layer with Molecular Beam Epitaxy technique. We have studied the properties of in-situ Cl-2-etched GaAs surfaces and overgrown QW structures as a function of the etching temperature (70 and 200 degrees C). Several models were used to fit the experimental points. Best fit to experimental points was obtained with the Passler model. (c) 2005 Elsevier B.V. All rights reserved.