Nanocluster formation by spin coating: Quantitative atomic force microscopy and Rutherford backscattering spectrometry analysis

Abstract

A recently developed spin coating method has been employed to produce a homogeneous distribution of nanometer-sized metal clusters onto a flat oxidic support. The particle size and distribution, and the total amount of material deposited has been studied by comparing the results of atomic force microscopy (AFM), Rutherford backscattering spectroscopy (RBS), and the appropriate hydrodynamic deposition equations. It is shown that the AFM is capable of producing a three-dimensional image of the surface which enables the particle number density and particle heights to be accurately determined. However, it is clear that as a result of tip convolution effects the particle diameter cannot be accurately determined. Using a hemispherical particle model the amount of material deposited during spin coating can be calculated from the AFM images. This calculation is shown to be accurate to approximately 50% in comparison with the results obtained from RBS. In contrast, it is shown that for a copper acetate precursor the predictions of the hydrodynamic equations are accurate to 2%. In the light of these results an assessment is made of the utility of AFM in the investigation of model catalyst systems and fundamental metal cluster studies.

Reaction of nanometer-sized Cu particles with a SiO2 substrate

“…The influence of changes in surface and interface energies on the course of the reaction may be even more pronounced when the surface and interface areas increase by spreading the silicide compound over the support. Although the tip-particle convolution in AFM experiments does not allow an exact determination of the size of the metallic Cu particles and the Cu-silicide islands, 10 an increase in area of the Cu species after UHV annealing by a factor of approximately 5-10 can be derived 3 from Fig. 1.…”

“…1͑a͔͒ is generally larger than the real diameter due to the tip-particle convolution. 10 Features of much larger dimensions are visible after annealing ͓Fig. 1͑b͔͒.…”

Magnetic properties of CoO nanoparticles

“…The preparation of the nanoparticles have been described in more detail for CuO in [6]. In this case, we used Co acetate, which was solved in ethanol, as a starting material.…”