Al0.3Ga0.7As/GaAs Quantum Well structures were grown by molecular beam epitaxy (MBE) on a 500 nm thick GaAs buffer layer subjected to the following surface processes: a) in-situ Cl-2 etching at 70 degrees C and 200 degrees C, b) air-exposure for 30 min. The characteristics of these samples were compared to those of a continuously grown sample with no processing (control sample). We obtained the quantum wells energy transitions using photo reflectance spectroscopy as a function of the temperature (8-300 K), in the range of 1.2 to 2.1 eV. The sample etched at 200 degrees C shows a larger intensity of the quantum well peaks in comparison to the others samples. We studied the temperature dependence of the excitonic energies in the quantum wells (QWs) as well as in GaAs using three different models: the first one proposed by Varshni [4], the second one by Vina et al. [5], and the third one by Passler and Oelgart [6]. The Passler model presents the best fitting to the experimental data. (C) 2009 Elsevier B.V. All rights reserved.