Radiative recombination of a 3D-electron with a 2D-hole in p-type GaAs/(GaAl)As heterojunctions

Abstract We have investigated an unusual new line observed in p-type GaAs/(AlGa)As heterojunctions, referred to as the H-band, by low-temperature photoluminescence experiments in magnetic fields up to 9.5 T. The direction of the magnetic field was turned from perpendicular to parallel to the interface. From the energetic shift, the splitting-behaviour, the lineshape and the temperature dependence of the luminescence line we conclude that the H-band is emitted by the recombination of a flat-band electron with a hole confined in an excited subband.