Publication

Abstract : Insight into the controlled growth features of nanowires has been in the prominent spotlight for engineering the material properties. Defect and dislocation induced nanowire growth has been emerging as a robust model by dwindling the conventional growth models. In this context, we have proposed a screw dislocated Eshelby twist origin in cationic assimilated ZnO nanowires synthesized via Successive Ionic Layer Absorption and Reaction (SILAR) technique. The growth of twisted nanowires occurred through a subsequent transformation from nanoflakes to nanoflowers. Presence of twist contours in various zone axis pattern provided strong validation of Eshelby origin in twisted nanowires. The preferential plane orientation of (0 0 0 2) confirmed the twisted growth along c-axis orientation. Presence of screw tail at the twisted end of nanowire confirmed the influence of Peach-Kohler force acted on the screw axis. Active vibrational modes and surface defect states of nanoflowers and nanowires were investigated and reported. Twisted ZnO nanowires showed maximum sensing response of 291 towards 100 ppm of ammonia at room temperature with the lowest detection limit of 5 ppm. The response and recovery times were found to be 39 and 17 s. Influence of grain alignment, grain orientation and potential barrier height on ammonia sensing signatures are reported.