Magnetophotoluminescence and magnetotransport were studied in a GaAs/AlGaAs triple quantum well. Oscillations of the photoluminescence intensity observed in tilted magnetic fields were found to correspond to the interlayer tunneling quantum Hall gap collapses detected in magnetoresistance measurements and predicted to occur in tilted magnetic fields. The obtained experimental data were shown to agree well with the theory developed for double quantum wells. This implies that the observed quantum Hall gap collapses are mostly caused by the tunneling between a pair of quantum wells. Our results reveal spectroscopic evidence of the quantum Hall gap collapses. Indications of interlayer correlation effects influencing a character of the inter-Landau-level gaps were found.

Photoluminescence was studied in GaAs/AlGaAs nanowires (NWs) with different radial heterostructures. We demonstrated that manipulation of the emission energy may be achieved by appropriate choice of the shell structure. The emission at highest energy is generated in the NWs with tunneling thin AlGaAs inner shell and thin GaAs outer shell due to recombination of the photoexcited electrons confined in the outer shell with the holes in the core. Lower energy emission was shown to occur in the NWs with thick outer shell grown in the form of a short-period GaAs/AlGaAs multiple quantum well structure. In this case, the tunneling probability through the multiple quantum wells controls the energy emitted by the NWs. The doping of core results in dominated low energy emission from the GaAs core. V C 2014 AIP Publishing LLC. [http://dx