Photoluminescence (PL) measurements are reported on modulation‐doped ordered‐GaInP2/ disordered‐GaInP2homojunctions. These junctions exhibit extremely high carrier densities of the two‐dimensional (2D) electron gas. A luminescence peak that involves recombination of these intrinsic 2D electrons and photoexcited holes shows a very large redshift as a result of the spatially separated carriers. However, no inverted S shaped behavior of PL energy is observed for this signal upon increasing temperature. This result affirms that the inverted S PL behavior of bulk ordered GaInP2has an extrinsic nature. ©1995 American Institute of Physics.