Interfacial profile of axial nanowire heterostructures in the nucleation limited regime

Heterostructured nanowires exhibit unique physical and electronic properties and are most commonly grown by the vapor-liquid-solid mechanism. Some of these properties are related to the interfacial abruptness of the heterointerface which makes its understanding and control particularly important for further development. In this regard, we present a model based on mass balance of atoms in the catalyst droplet where the atoms incorporate into the solid in the nucleation-limited regime. We explain how and why the decrease of growth temperature and increase of the flux of an element which forms a heterostructure leads to an improvement in the interface abruptness. Our model demonstrates that a sharp heterointerface can be obtained if one uses a high concentration of the foreign catalyst rather than self-catalyzed growth, which can be explained by a reduced reservoir effect. For the examples of InAs/GaAs and GaAs/AlAs heterostructures, we compare the compositional profiles for the two different heterointerface directions.