Mechanism and Kinetics of Spontaneous Nanotube Growth Driven by Screw Dislocations

Abstract

Single-crystal nanotubes are commonly observed, but their formation is often not understood. We show that nanotube growth can be driven by axial screw dislocations: Self-perpetuating growth spirals enable anisotropic growth, and the dislocation strain energy overcomes the surface energy required for creating a new inner surface forming hollow tubes spontaneously. This was demonstrated through solution-grown zinc oxide nanotubes and nanowires by controlling supersaturation using a flow reactor and confirmed using microstructural characterization. The agreement between experimental growth kinetics and those predicted from fundamental crystal growth theories confirms that the growth of these nanotubes is driven by dislocations.

Fe solubility, growth mechanism, and luminescence of Fe doped ZnO nanowires and nanorods grown by evaporation-deposition

“…In a dislocation-driven growth of the nanowires, an axial screw dislocation provides the self-perpetuating steps for unidimensional growth. This mechanism, demonstrated for some semiconductor nanowires, [10][11][12][13] was proposed by Sears 14 to explain the growth of whiskers. One difficulty in assessing the existence of a dislocation related growth in thin nanowires is that dislocations are not stable in small volumes, so they can move or be worked out during handling and are not observed in TEM.…”

“…However, even if a dislocation is not observed, other signs that result from screw dislocations, such as hollow tubes or Eshelby twist, can be considered. 11,12 According to the model of Frank, 15 hollow tubes, or nanopipes, can form in nanowires to reduce the elastic energy of an axial dislocation. Such nanopipes have been, for instance, observed in In 2 O 3 nanowires grown via evaporation-deposition.…”

Large-Scale Synthesis of Transition-Metal-Doped TiO2 Nanowires with Controllable Overpotential

“…[1][2][3][4][5][6][7][8][9] Many synthetic methods have been developed for growing one-dimensional (1D) semiconductors, including vaporliquid-solid (VLS), 10,11 vapor-solid (VS), 12 solution-liquid-solid (SLS), 13 and hydrothermal/solvothermal techniques. [14][15][16] However, these methods typically trade either yield for quality or vice versa. Since the future of 1D semiconductor nanotechnology depends on the balance between materials yield and subsequent device performance, 17 development of synthetic routes capable of simultaneously satisfying the needs of high yield, large-scale production, and high material quality continues to require great ingenuity.…”

“…25 To examine the transport and photoelectrochemical properties, nanowire electrodes were fabricated by drop-casting nanowires onto FTO substrates. From the slopes of the MottSchottky plots (Figure 4a & S6), carrier densities of undoped and 2 % Nb doped TiO 2 nanowires were estimated to be ~10 15 and ~10 21 cm -3 , respectively, using the following relation:…”

Research on Solid-phase Grinding Method of Manufacturing One-dimensional Zinc Oxide Nanomaterials Based on Nanosensors

“…In addition, ZnO nanostructures exhibit piezoelectric properties. Consequently, quasi-one-dimensional nanobelt structures have potential applications in micro-nanosensors, such as resonators, converters, and suspended bridges [6][7][8]. Besides, since ZnO has the advantages of negative electron affinity, high mechanical strength, high thermal stability, oxidation resistance and large exciton energy, it is superior to field emission.…”