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Knudsen diffusion in silicon nanochannels
Publikationstyp
Journal Article
Date Issued
2008-02-13
Sprache
English
Author(s)
Journal
Volume
100
Issue
6
Article Number
064502
Citation
Physical Review Letters 100 (6): 064502 (2008-02-13)
Publisher DOI
Scopus ID
ArXiv ID
Publisher
American Physical Society
Measurements on helium and argon gas flow through an array of parallel, linear channels of 12 nm diameter and 200 micrometer length in a single crystalline silicon membrane reveal a Knudsen diffusion type transport from 10^2 to 10^7 in Knudsen number Kn. The classic scaling prediction for the transport diffusion coefficient on temperature and mass of diffusing species,D_He ~ sqrt(T), is confirmed over a T range from 40 K to 300 K for He and for the ratio of D_He/D_Ar ~ sqrt(m_Ar/m_He). Deviations of the channels from a cylindrical form, resolved with transmission electron microscopy down to subnanometer scales, quantitatively account for a reduced diffusivity as compared to Knudsen diffusion in ideal tubular channels. The membrane permeation experiments are described over 10 orders of magnitude in Kn, encompassing the transition flow regime, by the unified flow model of Beskok and Karniadakis.
Subjects
Physics - Fluid Dynamics
Physics - Fluid Dynamics
Physics - Materials Science
Physics - Statistical Mechanics
Nonlinear Sciences - Exactly Solvable and Integrable Systems
Physics - Chemical Physics
DDC Class
530: Physik