Characterization of nanoparticles in the gas-borne state and on surface

Production of nano-particles via the gas phase is a desirable way for forming nanostructured materials. The production can be accomplished by either spraying a liquid to form liquid droplets and vaporizing the solvent containing nonvolatile materials, or by gas-to-particle conversion via nucleation, condensation and coagulation. We are interested in producing nano-particles of different semiconducting materials for making improved devices. The nano-particles must have a well defined size and be uniform in size (monodisperse). The performance of a condensation aerosol generator for producing nano-particles will be described. The nano-particles are measured and fractionated according to their sizes using a Differential Mobility Analyzer. The monodisperse particles are collected on appropriate substrates in an electrostatic precipitator. Their sizes and morphologies are determined by TEM - and AFM-Analyses. The limitations of this technology for producing the needed nano-particles are discussed.