Helical patterns are ubiquitous in nature, from snail shells to grapevines and the structure of DNA. Studying the characteristics of these structures, for example the pitch of the helix — the length in which one complete turn is made — can provide useful information on how such structures arise. Inorganic nanowires are known to have useful physical properties, but controlling the precise structures of these structures is an important requirement for exploting these properties for applications. Certain inorganic materials have been shown to form helical nanowires, but the mechanisms by which such structures grow are poorly understood.

Fig. 1: False colour image of the nanowires.

Now, Xiaodong Han and co-workers from Beijing University of Technology and the Chinese Academy of Sciences in Taiyuan, China and other collaborators1 have shown how a backbone structure of nanowires formed from silicon carbide is perfectly copied to produce daughter strands (Fig.1). The combination of the helical structure and the process which perfectly copies a ‘mother’ nanowire to produce a ‘daughter’ with identical structure is immediately reminiscent of DNA. “Understanding the growth mechanism of this structure provides clues to understand the growth of such structures in other semiconductor nanomaterials” says Han. “The mechanism we have elucidated here should be general for other materials with a zincblende type structure.”

The next step for Han and co-workers will be to investigate the mechanical properties of the nanowires. The resemblance of the growth mechanism to that of DNA also points to potential applications. “There have been many reports which show that DNA can wrap around carbon nanotubes,” says Han. “We expect to be able to wrap DNA around these nanowires in a similar fashion, and that applications of this technology will be found in for example DNA sorting and sensing.”