Current imaging and electromigration-induced splitting of GaN nanowires as revealed by conductive atomic force microscopy.
Current images of electromigration-induced common vapor-liquid-solid-grown GaN nanowires were obtained using a conductive atomic force microscope. Structural characterization indicated that these wurtzite (ZW) [0110] nanowires contained longitudinal zinc blende (ZB) defects as stacking faults. The current was attributed to tunneling current through the Schottky barrier between the AFM tip and a nanowire, which was dominated by the local nanowire surface work function. Due to the electromigration induced by large current densities around the defects, the axial splitting process of the nanowires was directly observed under continuous current scanning. The electromigration was likely enhanced by non-uniformly distributed electrostatic pressure around the axial ZW/ZB domain interfaces.