However, many aspects of nanowire growth are beyond the scope of simple arguments based on near equilibrium growth controlled by surface energies. Changes in the growth direction reflect competing catalyst/silicon-nanowire interface and silicon-nanowire surface energetics. Thorough investigations have shown that the pressure in the nanowire synthesis process provides selective control over the growth direction. By dynamically changing the system pressure during the VLS growth process, morphological changes of the nanowire growth directions along their length have been demonstrated, resulting in zig-zag fashioned nanowires.

The nanowire shown in the figure above has three sections well separated by two kinks. The upper and the lowest part of the Si-NW with (111( growth direction and between them a central part growing along the [21-1] direction.

In the future, the optoelectronic transport (low loss coupling and transmission) properties of such zig-zag nanowires will be investigated to assess their potential as building blocks for silicon photonics systems. Silicon nanophotonic waveguides in a complementary metal-oxide-semiconductor (CMOS)-compatible silicon-on-insulator platform may result in further integration of optical and electrical circuitry.

The researchers presented their work in Nanotechnology.