Strain mapping in free-standing heterostructured wurtzite InAs/InP nanowires

The strain distribution in heterostructured wurtzite InAs/InP nanowires is measured by a peak finding technique using high resolution transmission electron microscopy images. We find that nanowires with a diameter of about 20 nm show a 10 nm strained area over the InAs/InP interface and the rest of the wire has a relaxed lattice structure. The lattice parameters and elastic properties for the wurtzite structure of InAs and InP are calculated and a nanowire interface is simulated using finite element calculations. Both the method and the experimental results are validated using a combination of finite element calculations and image simulations.