Print Email Facebook Twitter Simulation of atomic layer deposition on nanoparticle agglomerates Title Simulation of atomic layer deposition on nanoparticle agglomerates Author Jin, W. (TU Delft ChemE/Product and Process Engineering) van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering) Kleijn, C.R. (TU Delft ChemE/Transport Phenomena) Date 2016-11 Abstract Coated nanoparticles have many potential applications; production of large quantities is feasible by atomic layer deposition (ALD) on nanoparticles in a fluidized bed reactor. However, due to the cohesive interparticle forces, nanoparticles form large agglomerates, which influences the coating process. In order to study this influence, the authors have developed a novel computational modeling approach which incorporates (1) fully resolved agglomerates; (2) a self-limiting ALD half cycle reaction; and (3) gas diffusion in the rarefied regime modeled by direct simulation Monte Carlo. In the computational model, a preconstructed fractal agglomerate of up to 2048 spherical particles is exposed to precursor molecules that are introduced from the boundaries of the computational domain and react with the particle surfaces until these are fully saturated. With the computational model, the overall coating time for the nanoparticle agglomerate has been studied as a function of pressure, fractal dimension, and agglomerate size. Starting from the Gordon model for ALD coating within a cylindrical hole or trench [Gordon et al., Chem. Vap. Deposition 9, 73 (2003)], the authors also developed an analytic model for ALD coating of nanoparticles in fractal agglomerates. The predicted coating times from this analytic model agree well with the results from the computational model for Df = 2.5. The analytic model predicts that realistic agglomerates of O(10⁹) nanoparticles require coating times that are 3–4 orders of magnitude larger than for a single particle. Subject FractalsAtomic layer depositionNanoparticlesSelf diffusionComputational models To reference this document use: http://resolver.tudelft.nl/uuid:2f3cec24-655b-471b-a49e-ad45ecf775c0 DOI https://doi.org/10.1116/1.4968548 Embargo date 2017-11-29 ISSN 0734-2101 Source Journal of Vacuum Science and Technology. Part A: International Journal Devoted to Vacuum, Surfaces, and Films, 35 (1), 1-7 Part of collection Institutional Repository Document type journal article Rights © 2016 W. Jin, J.R. van Ommen, C.R. Kleijn Files PDF 1.4968548.pdf 2.23 MB Close viewer /islandora/object/uuid:2f3cec24-655b-471b-a49e-ad45ecf775c0/datastream/OBJ/view