Conduction electrons bound to magneto-donors and magneto-acceptors in GaAs/GaAlAs quantum wells

Interband photoluminescence from asymmetric modulation-doped GaAs---GaAlAs quantum wells in the presence of a magnetic field has been investigated. The free-carrier Landau level excitations as well as transitions between magneto-donor and free hole states have been observed. Experiments with tilted magnetic field provide strong evidence for the existence of conduction electrons bound to ionized magneto-acceptors, characterized by discrete energies above the conduction band Landau levels. The observations are compared with the theory.