AVS 54th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP36
Preparation and Chemical Modification of Nanoparticle Layers by Plasma Treatments

Tuesday, October 16, 2007, 6:00 pm, Room 4C

Session: Surface Science Poster Session
Presenter: M. Baeumer, University Bremen, Germany
Authors: B. Gehl, University Bremen, Germany
A. Frömsdorf, University Hamburg, Germany
V. Aleksandrovic, University Hamburg, Germany
T. Schmidt, University Bremen, Germany
J. Falta, University Bremen, Germany
H. Weller, University Hamburg, Germany
M. Baeumer, University Bremen, Germany
Correspondent: Click to Email

Nanoparticles deposited as thin films on oxidic substrates represent a highly interesting class of materials systems not only for physical (e.g. magnetic) but also chemical applications, such as heterogeneous catalysis for example. A flexible and relatively simple way to prepare such layers is to wet-chemically synthesize nanoparticles in colloidal solution and deposit them onto a flat substrate by spincoating or a comparable method. In most cases the as-prepared particles are surrounded by a shell of organic molecules stabilizing the colloidal suspended state. To freely access the properties of the metallic particle surface for measurement or application, it is necessary to remove this shell of physically obstructing and chemically passivating ligands. It is important that the method used to strip the particles of their organic sheath neither disturbs the particle material, the substrate nor the structure of the layer. This can be achieved by exposing the deposited nanoparticles to a mild plasma removing the ligand shell through a combination of sputtering and etching processes with free radicals. It will be demonstrated that both reducing and oxidizing plasmas can be used for this purpose. Moreover, by varying plasma gasses and parameters, it is also possible to modify the chemical state of the particles selectively but leaving the lateral arrangement on the surface undisturbed. The contribution will shed light on the possibilities and limits of the approach also comparing the results to experiments where the ligand shell was removed by thermal treatment. Another aspect that will be addressed is the risk of chemical interactions with the support material induced by the plasma treatment.