Photoluminescence of radial heterostructured GaAs/AlGaAs/GaAs nanowires

Photoluminescence (PL) of high-density GaAs nanowires (NWs) encapsulated by a double AlGaAs/GaAs shell is studied. Two lines are found and assigned to the radiative recombinations of photoexcited electrons confined in the center of the GaAs core and at the heteroboundary between the outer GaAs shell and the inner AlGaAs one with the holes in the core and the holes confined at the heteroboundary between the core and the inner AlGaAs shell. The simple model, based on representation of the valence band structure using two levels, well accounts for the observed temperature dependence of the integrated photoluminescence intensities. The proposed double shell structure with tunneling transparent inner shell sets conditions for easy control of the emission energy of the heterostructured nanowires.