The H-Band Luminescence of p-Type GaAs-(GaAl)As Heterostructures in High Magnetic Fields

We have investigated p-type GaAs-(GaAl)As heterojunctions by low temperature photoluminescence experiments in magnetic fields up to 9.5 T. The H-band luminescence splits in two well resolved lines denoted as e- and d-line respectively. From the energy shift and the splitting-behaviour, we conclude that the a-line is emitted by the recombination of a (3D)-flat-band electron with a (2D)-hole confined in an excited subband near the interface. In the case of the d-line the electron stems from a donor.