High-temperature annealing of thin Au films on Si: Growth of SiO2 nanowires or Au dendritic nanostructures?

Abstract

A simple and low-cost approach for the large-scale production of Au nanodendritic structures on Si is presented. Starting from the methodology involving deposition of a Au film on Si and heating the system to high temperatures in an inert ambient containing trace amounts of oxygen for the growth of SiO2 nanowires (NWs), we show that a suppression of the NWs growth and a promotion of the growth of Au nanodendrites occur when fast heating and cooling rates are used. We analyze the nanodendrites formation process considering the kinetics processes at the Au/Si interface in far from thermodynamic equilibrium situation.

Silica nanowire–Au nanoparticle pea-podded composites: Synthesis and structural analyses

“…Amorphous SiO x NWs can be grown on a crystalline Si substrate by first depositing a thin metal film (Au, for example) on its surface and then heating the system to elevated temperatures (N1273 K) in an inert ambient (e.g. N 2 or Ar) containing trace amounts (3-5 ppm) of oxygen [2,3,[7][8][9][10][11][12][13][14][15]. Considering, for example, a thin Au film on the Si substrate, it is widely recognized [8,16] that, during the heating, the film breaks up into nanometer-scale islands and reacts with the Si substrate to form molten droplets of Au-Si eutectic composition (in fact, the Au/Si phase diagram has an eutectic point at 636 K corresponding to 18.6 at.% of Au, see Fig.…”

“…As usually recognized[2,3,[7][8][9][10][11][12][13][14][15][16], the sample surface shows a grass-like array of nanowires which surface density increases with increasing the growth time. The obtained NWs are well-defined, with diameters of about 20-500 nm and lengths up to 20 μm.…”

Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

“…It seems that in the case of directional solidification of eutectics as a method of manufacturing of nanostructures, the platforms are homogeneous. Unfortunately, as it can be found in literature, that eutectic-based growth may lead to an increase of inclusions of another phase in metallic structures [2,4–6]. When nanostructures are formed from thin metal films, directional eutectic growth is not the only process that needs to be considered.…”

Au impact on GaAs epitaxial growth on GaAs (111)B substrates in molecular beam epitaxy

“…In the case of annealing Au thin films on Si (001) substrates, complex Au-Si droplet behaviour and different surface nanostructures have been observed. 27,28 On the other hand, the structural behaviour of interfaces between Au thin films and GaAs substrates has been investigated because this system has been consequently used as ohmic contacts. 29,30 However, detailed role of Au nanoparticles on the GaAs surfaces during the annealing is not clear, although the evolution of Au containing droplets in Au coated GaAs substrates depends strongly upon the environmental conditions.…”