Deposition of aerosol nanoparticles on flat substrate surfaces

The deposition process in a homogeneous electric field, and the subsequent microscopic arrangement of charged, metallic aerosol nanoparticles in the size range of 30 nm on flat substrate surfaces is described. The first aspect of the investigation is the transfer of the particles from a three-dimensional distribution in the gas phase into their arrangement on the substrate surface, in dependence on particle-particle interactions and on Brownian motion. The theoretical results obtained with a trajectory model are compared with experimental results obtained by scanning electron microscope investigation of the deposition patterns. The second aspect of the investigation is the nanostructured arrangement of nanoparticles by means of inhomogeneous electric microfields. We demonstrate a parallel process for the transfer of charge patterns on oxidized silicon surfaces followed by the deposition of monodisperse singly charged nanoparticles, which allows the creation of particle arrangements reaching from 100 nm resolution up to structures in the upper micrometer range. The charge patterns are transferred using a polydimethylsiloxane (PDMS)-stamp, which is covered with a metal layer

Nanostructured deposition of nanoparticles from the gas phase

For many applications, nanoparticles from the gas phase are of interest due to their physical properties. Especially for electronic or optoelectronic applications, the transfer from their random distribution in the gas phase onto flat. substrate surfaces has to be controlled because the particles are needed in exactly defined areas on the substrate. We demonstrate a parallel process for the transfer of charge patterns on oxidized silicon surfaces followed by the deposition of mono-disperse singly charged nanoparticles, which allows the creation of particle arrangements reaching from 100 nm resolution up to structures in the upper micrometer range. The charge patterns are transferred using a polydimethylsiloxane (PDMS) stamp, which is covered with a metal layer. By applying different voltages to the stamp, negative or positive charges can be transferred. Thus, nanoparticles of different polarities can be guided to certain places

Microscopic aspects of the deposition of nanoparticles from the gas phase

The deposition process in a homogeneous electric field, and the subsequent microscopic arrangement of charged, metallic nanoparticles in the size range below 100 nm on flat substrate surfaces is described. The main aspect of the investigation is the transfer of the particles from a three-dimensional distribution in the gas phase into their arrangement on the substrate surface, in dependence on particle-particle interactions and on Brownian motion. For this purpose, a trajectory model has been developed, which takes into account the flow field above the substrate surface, the electric field, the interactions of incoming particles with the substrate surface and with already deposited particles, as well as Brownian motion. The results from the trajectory calculations are compared with experimental results, obtained by scanning electron microscopy investigations of deposition patterns, created by deposition of indium and gold nanoparticles in an electrostatic precipitator. The particle diameter, the particle charge, the substrate material, the electric field strength and the number of particles deposited per unit area have been varied. (C) 2002 Elsevier Science Ltd. All rights reserved