Axial nanowire heterostructures composed of InSb on top of InP are grown via the vapor-liquid-solid process using metalorganic precursors and liquid indium as the catalyst. Scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, and high-resolution X-ray diffraction are used to determine the morphology, crystallinity, and composition of the heterostructures. We find that the InP is zinc blende in structure while the InSb segments are composed of both wurtzite and zinc blende structures. Interestingly, we observe the InP/InSb interfaces to be composed of elastically strained InSb and/or Sb-rich In(P,Sb) alloy layers. (C) 2011 Elsevier B.V. All rights reserved.