Abstract We report electrical properties of the two dimensional electron gas in selectively S- and Si-doped GaInP/GaAs heterostructures grown by Low Pressure MOCVD. The influence of the spacer thickness on the sheet carrier density derived from Shubnikov-de Haas oscillations is analyzed. Persistent photoconductivity is studied through the temperature dependence of the Hall effect and is used to increase the electronic density. At each step of illumination the classical to quantum lifetimes ratio is derived and an increase of this ratio is observed. Comparison with AlGaAs/GaAs heterostructures shows that DX-like centers are not necessarily responsible for the origin of the observed persistent photoconductivity effect.