Outermost AlGaO x native oxide as a protection layer for GaAs/AlGaAs core-multishell nanowires

We propose native oxide AlGaOx outer protective layer for GaAs/AlGaAs core-multishell nanowires to provide yearly stable stronger optical and electrical confinement within the nanowire core. We prepared core-multishell NWs consisting of GaAs core, Al0.2Ga0.8As multi-layered barrier layer, and amorphous Al0.9Ga0.1Ox outer shell, which was obtained simply by growing Al-rich AlGaAs and exposing the NWs to the ambient air. Photoluminescence from the NWs reveals that the Al0.9Ga0.1Ox outer shell provides efficient optical confinement and creates a compressive strain in the interior of the NW that enhances and blueshifts the photoluminescence of the GaAs core.