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Ledge-flow-controlled catalyst interface dynamics during Si nanowire growth


Self-assembled nanowires offer the prospect of accurate and scalable device engineering at an atomistic scale for applications in electronics, photonics and biology. However, deterministic nanowire growth and the control of dopant profiles and heterostructures are limited by an incomplete understanding of the role of commonly used catalysts and specifically of their interface dynamics1,2. Although catalytic chemical vapour deposition of nanowires below the eutectic temperature has been demonstrated in many semiconductor–catalyst systems3,4,5,6, growth from solid catalysts is still disputed and the overall mechanism is largely unresolved. Here, we present a video-rate environmental transmission electron microscopy study of Si nanowire formation from Pd silicide crystals under disilane exposure. A Si crystal nucleus forms by phase separation, as observed for the liquid Au–Si system, which we use as a comparative benchmark. The dominant coherent Pd silicide/Si growth interface subsequently advances by lateral propagation of ledges, driven by catalytic dissociation of disilane and coupled Pd and Si diffusion. Our results establish an atomistic framework for nanowire assembly from solid catalysts, relevant also to their contact formation.

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Figure 1: SiNW nucleation from liquid and solid catalysts.
Figure 2: Pd-silicide-mediated nanowire growth rate.
Figure 3: Ledge-flow-controlled catalyst interface dynamics.


  1. Wagner, R. S. in Whisker Technology (ed. Levitt, A. P.) (Wiley, New York, 1970).

    Google Scholar 

  2. Hiruma, K. et al. Growth and optical properties of nanometer-scale GaAs and InAs whiskers. J. Appl. Phys. 77, 447–462 (1995).

    Article  CAS  Google Scholar 

  3. Kamins, T. I., Williams, R. S., Basile, D. P., Hesjedal, T. & Harris, J. S. Ti-catalyzed Si nanowires by chemical vapor deposition: Microscopy and growth mechanisms. J. Appl. Phys. 89, 1008–1016 (2001).

    Article  CAS  Google Scholar 

  4. Persson, A. I. et al. Solid-phase diffusion mechanism for GaAs nanowire growth. Nature Mater. 3, 677–681 (2004).

    Article  CAS  Google Scholar 

  5. Wang, Y. W., Schmidt, V., Senz, S. & Gosele, U. Epitaxial growth of silicon nanowires using an aluminium catalyst. Nature Nanotechnol. 1, 186–189 (2006).

    Article  CAS  Google Scholar 

  6. Kodambaka, S., Tersoff, J., Reuter, M. C. & Ross, F. M. Germanium nanowire growth below the eutectic temperature. Science 316, 729–732 (2007).

    Article  CAS  Google Scholar 

  7. Park, H. D., Gaillot, A.-C., Prokes, S. M. & Cammarata, R. C. Observation of size dependent liquidus depression in the growth of InAs nanowires. J. Cryst. Growth 296, 159–164 (2006).

    Article  CAS  Google Scholar 

  8. Adhikari, H., Marshall, A. F., Chidsey, C. E. D. & McIntyre, P. C. Germanium nanowire epitaxy: Shape and orientation control. Nano Lett. 6, 318–323 (2006).

    Article  CAS  Google Scholar 

  9. Howe, J. M. Interfaces in Materials (Wiley, New York, 1997).

    Google Scholar 

  10. Jackson, K. A. The present state of the theory of crystal growth from the melt. J. Cryst. Growth 24–25, 130–136 (1974).

    Article  Google Scholar 

  11. Hannon, J. B., Shenoy, V. B. & Schwarz, K. W. Anomalous spiral motion of steps near dislocations on silicon surfaces. Science 313, 1266–1269 (2006).

    Article  CAS  Google Scholar 

  12. Mangin, P., Marchal, G., Mourey, C. & Janot, C. Physical studies of Au(x)Si(1-x) amorphous alloys. Phys. Rev. B 21, 3047–3056 (1980).

    Article  CAS  Google Scholar 

  13. Shpyrko, O. G. et al. Surface crystallization in a liquid AuSi alloy. Science 313, 77–80 (2006).

    Article  CAS  Google Scholar 

  14. Baxi, H. C. & Massalski, T. B. The Pd–Si System. J. Phase Equilib. 12, 349–356 (1991).

    Article  CAS  Google Scholar 

  15. Hofmann, S. et al. In situ observations of catalyst dynamics during surface-bound carbon nanotube nucleation. Nano Lett. 7, 602–608 (2007).

    Article  CAS  Google Scholar 

  16. Wu, Y. et al. Controlled growth and structures of molecular-scale silicon nanowires. Nano Lett. 4, 433–436 (2004).

    Article  CAS  Google Scholar 

  17. Cherns, D., Smith, D. A., Krakow, W. & Batson, P. E. Electron-microscope studies of the structure and propagation of the Pd2Si-(111)Si interface. Phil. Mag. A 45, 107–125 (1982).

    Article  CAS  Google Scholar 

  18. Rubloff, G. W. Microscopic properties and behavior of silicide interfaces. Surf. Sci. 132, 268–314 (1983).

    Article  CAS  Google Scholar 

  19. Kodambaka, S., Tersoff, J., Reuter, M. C. & Ross, F. M. Diameter-independent kinetics in the vapor–liquid–solid growth of Si nanowires. Phys. Rev. Lett. 96, 096105 (2006).

    Article  CAS  Google Scholar 

  20. Liau, Z. L., Campisano, S. U., Canali, C., Lau, S. S. & Mayer, J. W. Kinetics of the initial stage of Si transport through Pd-silicide for epitaxial growth. J. Electrochem. Soc. 122, 1696–1699 (1975).

    Article  CAS  Google Scholar 

  21. Goesele, U. in Alloying (eds Walter, J. L., Jackson, M. R. & Sims, C. T.) (ASM, Ohio, 1988).

    Google Scholar 

  22. Lee, S. W., Jeon, Y. C. & Joo, S. K. Pd induced lateral crystallization of amorphous Si thin-films. Appl. Phys. Lett. 66, 1671–1673 (1995).

    Article  CAS  Google Scholar 

  23. Hesse, D., Werner, P., Mattheis, R. & Heydenreich, J. Interfacial reaction barriers during thin-film solid-state reactions—the crystallographic origin of kinetic barriers at the NiSi2/Si(111) interface. Appl. Phys. A 57, 415–425 (1993).

    Article  Google Scholar 

  24. Frank, F. C. The influence of dislocations on crystal growth. Discuss. Faraday Soc. 5, 48–54 (1949).

    Article  Google Scholar 

  25. Landolt-Bornstein (ed.) Diffusion in Semiconductors III/33 (Springer, Berlin, 1998).

  26. Weber, W. M. et al. Silicon-nanowire transistors with intruded nickel-silicide contacts. Nano Lett. 6, 2660–2666 (2006).

    Article  CAS  Google Scholar 

  27. Saka, H., Sasaki, K., Tsukimoto, S. & Arai, S. In situ observation of solid–liquid interfaces by transmission electron microscopy. J. Mater. Res. 20, 1629–1640 (2005).

    Article  CAS  Google Scholar 

  28. Sharma, R. An environmental transmission electron microscope for in situ synthesis and characterization of nanomaterials. J. Mater. Res. 20, 1695–1707 (2005).

    Article  CAS  Google Scholar 

  29. Yokota, T., Murayama, M. & Howe, J. M. In situ transmission-electron-microscopy investigation of melting in submicron Al–Si alloy particles under electron-beam irradiation. Phys. Rev. Lett. 91, 265504 (2003).

    Article  Google Scholar 

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S.H. acknowledges funding from Peterhouse, S.H. and C.D. from the Royal Society. F.C.-S. acknowledges CONACyT Mexico.

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Hofmann, S., Sharma, R., Wirth, C. et al. Ledge-flow-controlled catalyst interface dynamics during Si nanowire growth. Nature Mater 7, 372–375 (2008).

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