abstract-Interfacial abruptness in axial heterostructures within III-V nanowires (NWs) grown by the vapor-liquid-solid (VLS) method is affected by the reservoir effect in catalyst droplets which broadens the heterointerfaces. Here, we present a model which provides explicitly the interfacial profiles in double NW heterostructures based on group V interchange of any composition, and fit the data on Au-catalyzed InP/InAs/InP, self-catalyzed GaAs0.6P0.4/GaxAsxP1-x/GaAs0.6P0.4 and GaP/GaAsxP1-x/GaP axial NW heterostructures.