Au Nanoparticles on SiO2

ALI-1000 Deposition System

In the last decade, the use of nanoparticles has extended to different fields of research. Nanoparticles can be produced in many different ways, one of these being epitaxial growth in UHV. However, in some cases, instead of growing the nanoparticles in UHV, we may wish to deposit nanoparticles that have been produced ex-situ. For these cases, ALI deposition system is an ideal solution.
MORE INFOA single drop of a colloid of 20 nm gold nanoparticles deposited by ALI has been analyzed using a scanning electron microscope (SEM). Colloid: 0.01% tannic acid, 0,04% trisodium citrate, and 0.01% HAuCl4.

The figure on the right shows four SEM images of gold nanoparticles on a Si wafer. These were obtained after a 200mbar injection of a gold nanoparticle colloid with a density of 1012 particles/ml. On the left side of the figure a drop and its detail are shown, obtained with an ALI-sample distance of 191.3 mm. On the right the distance was 206.5 mm. In both images the distribution of the remaining material after the drop’s evaporation is inhomogeneous. Most of the nanoparticles are located at the edge of the drop on the surface. The zoom images confirm that the material is formed by gold nanoparticles with an average size around 20 nm.

Substrate

SiO2


Solute

Au nanoparticles (ca 20nm)


Solvent

H2O, <0.01% tannic acid, <0.04% sodium citrate, 0.01% HAuCl4


Concentration

ca 103 particles/ml


Inj. Conditions

p=1000mbar, 10 x [topen=100; tclose=120s]