Rotary reactor for atomic layer deposition on large quantities of nanoparticles
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309 (United States)
Challenges are encountered during atomic layer deposition (ALD) on large quantities of nanoparticles. The particles must be agitated or fluidized to perform the ALD surface reactions in reasonable times and to prevent the particles from being agglomerated by the ALD film. The high surface area of nanoparticles also demands efficient reactant usage because large quantities of reactant are required for the surface reactions to reach completion. The residence time of the reactant in a fluidized particle bed reactor may be too short for high efficiency if the ALD surface reactions have low reactive sticking coefficients. To address these challenges, a novel rotary reactor was developed to achieve constant particle agitation during static ALD reactant exposures. In the design of this new reactor, a cylindrical drum with porous metal walls was positioned inside a vacuum chamber. The porous cylindrical drum was rotated by a magnetically coupled rotary feedthrough. By rotating the cylindrical drum to obtain a centrifugal force of less than one gravitational force, the particles were agitated by a continuous 'avalanche' of particles. In addition, an inert N{sub 2} gas pulse helped to dislodge the particles from the porous walls and provided an efficient method to purge reactants and products from the particle bed. The effectiveness of this rotary reactor was demonstrated by Al{sub 2}O{sub 3} ALD on ZrO{sub 2} particles. A number of techniques including transmission electron microscopy, Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy confirmed that the Al{sub 2}O{sub 3} ALD film conformally coats the ZrO{sub 2} particles. Combining static reactant exposures with a very high surface area sample in the rotary reactor also provides unique opportunities for studying the surface chemistry during ALD.
- OSTI ID:
- 20853951
- Journal Information:
- Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 25, Issue 1; Other Information: DOI: 10.1116/1.2393299; (c) 2007 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM OXIDES
CYLINDRICAL CONFIGURATION
DEPOSITION
FILMS
FOURIER TRANSFORM SPECTROMETERS
INFRARED SPECTRA
LAYERS
METALS
NANOSTRUCTURES
PARTICLES
POROUS MATERIALS
SURFACE AREA
SURFACES
TRANSMISSION ELECTRON MICROSCOPY
VAPOR DEPOSITED COATINGS
X-RAY PHOTOELECTRON SPECTROSCOPY
ZIRCONIUM OXIDES