In this study, the photoluminescence measurements of GaAs/AlGaAs multi-quantum-wells heterojunction structure grown on n+-GaAs substrates by Metal Organic Vapor Phase Epitaxy (MOVPE) method are investigated. By dropping 5145 Å wavelength laser light on the sample at room temperature and low temperatures, the transitions between the bands in the structure and the changes in these transitions under the different electric fields and temperatures are observed. In addition, by making theoretically developed self-consistent potential calculations, the subband energy levels and their corresponding wave functions of the structure under the electric field and without the electric field are calculated. The obtained numerical results were found to be in full agreement with the experimental measurements and theoretical calculations.