Crystal-phase control of GaAs-GaAsSb core-shell/axial nanowire heterostructures by a two-step growth method

The growth of III-Sb nanowires with controlled wurtzite and zinc-blende structures is essential for tailoring their fundamental properties and in turn potential applications. However, most studies of III-Sb nanowires have shown that they adopt the zinc-blende structure, so that the growth of wurtzite structured III-Sb nanowires needs to be explored. In this study, both wurtzite and zinc-blende structured GaAs-GaAsSb core-shell nanowire heterostructures and axial heterostructures were grown by tuning the crystal structure of nanowire cores and varying the Sb flux. Our aberration-corrected electron microscopy investigations suggest that the nanowire shells maintained the same crystal structure as their nanowire cores. Besides, it was found that the axial-lateral GaAs-GaAaSb heterostructures were grown with increasing the Sb flux, due to the increased Sb supersaturation at the catalyst-nanowire interface. This study provides an avenue for growing III-Sb nanowires with desired crystal structures in order to secure different properties.