Facilitating growth of InAs–InP core–shell nanowires through the introduction of Al

摘要: InAs nanowires were grown on GaAs substrates by the Au-assisted vapour–liquid–solid (VLS) method in a gas source molecular beam epitaxy (GSMBE) system. Passivation of using InP shells proved difficult due to tendency for formation axial rather than core–shell structures. To circumvent this issue, AlxIn1−xAs or AlxIn1−xP with nominal Al composition fraction x=0.20, 0.36, 0.53 direct vapour–solid deposition sidewalls nanowires. Characterisation transmission electron microscopy revealed that addition shell resulted remarkable transition from VLS growth mode uniform thickness along nanowire length. Possible mechanisms include reduced adatom diffusion, phase change Au seed particle, and surfactant effects. The InAs–AlInP core-shell exhibited misfit dislocations, while InAs–AlInAs lower strain appeared be free dislocations.