We control the formation of Bi-induced nanostructures on the growth of GaAs/GaAsBi core–shell nanowires (NWs). Bi serves as not only a constituent but also a surfactant and nanowire growth catalyst. Thus, we paved a way to achieve unexplored III–V nanostructures employing the characteristic supersaturation of catalyst droplets, structural modifications induced by strain, and incorporation into the host GaAs matrix correlated with crystalline defects and orientations. When Ga is deficient during growth, Bi accumulates on the vertex of core GaAs NWs and serves as a nanowire growth catalyst for the branched structures to azimuthal <112>. We find a strong correlation between Bi accumulation and stacking faults. Furthermore, Bi is preferentially incorporated on the GaAs (112)B surface, leading to spatially selective Bi incorporation into a confined area that has a Bi concentration of over 7%. The obtained GaAs/GaAsBi/GaAs heterostructure with an interface defined by the crystalline twin defects in a zinc-blende structure can be potentially applied to a quantum confined structure. Our finding provides a rational design concept for the creation of GaAsBi based nanostructures and the control of Bi incorporation beyond the fundamental limit.

We propose native oxide AlGaOx outer protective layer for GaAs/AlGaAs coremultishell 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.

GaAs/AlGaAs core-shell nanowires with AlGaOx outermost shell layer, typically having 250 nm diameter and 7 µm length, were grown on 2-inch Si wafer by the single process of molecular beam...

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