Description: Das Projekt "Herstellung von Nanopartikeln mittels Verdampfungs- und Kondensationsprozessen" wird vom Umweltbundesamt gefördert und von Universität Duisburg, Fachbereich 9 Elektrotechnik, Fachgebiet Prozess- und Aerosolmesstechnik durchgeführt. Nanostructured materials are receiving increasingly interest as building blocks for nanotechnological applications, such as nanoelectronics, quantum electronics, sensortechnology, non-linear optics and solar technology. A layer of semiconducting nanoparticles smaller than 20 nm on a well-defined surface will have properties which differ from the bulk material, for indstance a modified bandgap and specific opto-eletronic properties. Here, gas-phase synthesis is advantageous becaus of absence of liquid solvents and the possiblility of reaching high temperatures. The synthesis technique consists of modified standard aerosol technologies to generate monodisperse size fraction. In a furance a specific solid material is heated, and during the cooling of the vapor nanometer-sized particles are formed by nucleation, condensation and coagulation. The modeling of the process is carried out using the methods of moments. The gas is quenched and a specific size-fraction is selected based on the size-dependent electrical mobility (Differential Mobility Analyzer). A new unipolar particle charger has been developed in order to increase the carging efficiency of nanoparticles. In a second furance the particles, which might consist of aggregated primary particles, can be sintered in order ot reach a more spherical form. An electrostatic precipitator is used to bring the particles on a specific surface, e.g. a THEM grid. Instead of the precipitator a second DMA can be used to check the sintering process. The present research is focused on ObS, which was shown to yield nanoparticles by a sublimation process. A study was made of the sintering behavior which was shown to be necessary to abtain spherical and crystalline particles. X-ray diffraction and electron diffraction in cooperation with Low Temperature Physics (Prof. Wassermann) enable the determination of the lattice constant and the crystallite size. The results indicated that the PbS particles are fully crystalline with a lattice constant of bulk PbS. The prospects of applying the semiconductor particles in microelectronics are investigated in cooperation with Seminconductor Technology (Prof. Tegude). Combining optical lithography with electrostatic particle deposition, it was shown that the PbS nanoparticles deposited on top of a metalsemiconductor-metal photodetecotr increased the sensitivity up to several orders of magnitude.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Duisburg ? Sinterung ? Röntgenstrahlung ? Elektrofilter ? Elektronik ? Lösungsmittel ? Optik ? Aerosol ? Elektrotechnik ? Feststoff ? Flockung ? Solartechnik ? Gasförmiger Stoff ? Analysegerät ? Koagulation ? Kondensation ? Partikelförmige Luftverunreinigung ? Mikroelektronik ? Studie ? Deposition ? Schüttgut ? Modellierung ? Nanopartikel ? REACH ? Brüdenkompression ? Halbleiter ? Partikel ? Verdampfung ?
Region: Nordrhein-Westfalen
Bounding box: 6.76339° .. 6.76339° x 51.21895° .. 51.21895°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1995-07-01 - 2001-06-30
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