Scale-dependent diffusion anisotropy in nanoporous silicon.

Kondrashova D, Lauerer A, Mehlhorn D, Jobic H, Feldhoff A, Thommes M, Chakraborty D, Gommes C, Zecevic J, De Jongh P, Bunde A, Kärger J, Valiullin R (2017)

Publication Type: Journal article, Original article

Subtype: other

Publication year: 2017


Publisher: Nature Publishing Group

Book Volume: 7

Pages Range: 40207

DOI: 10.1038/srep40207


Nanoporous silicon produced by electrochem. etching of highly B-doped p-type silicon wafers can be prepd. with tubular pores imbedded in a silicon matrix. Such materials have found many technol. applications and provide a useful model system for studying phase transitions under confinement. This paper reports a joint exptl. and simulation study of diffusion in such materials, covering displacements from mol. dimensions up to tens of micrometers with carefully selected probe mols. In addn. to mass transfer through the channels, diffusion (at much smaller rates) is also found to occur in directions perpendicular to the channels, thus providing clear evidence of connectivity. With increasing displacements, propagation in both axial and transversal directions is progressively retarded, suggesting a scale-dependent, hierarchical distribution of transport resistances ("constrictions" in the channels) and of shortcuts (connecting "bridges") between adjacent channels. The exptl. evidence from these studies is confirmed by mol. dynamics (MD) simulation in the range of atomistic displacements and rationalized with a simple model of statistically distributed "constrictions" and "bridges" for displacements in the micrometer range via dynamic Monte Carlo (DMC) simulation. Both ranges are demonstrated to be mutually transferrable by DMC simulations based on the pore space topol. detd. by electron tomog. [on SciFinder(R)]

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Kondrashova, D., Lauerer, A., Mehlhorn, D., Jobic, H., Feldhoff, A., Thommes, M.,... Valiullin, R. (2017). Scale-dependent diffusion anisotropy in nanoporous silicon. Scientific Reports, 7, 40207.


Kondrashova, Daria, et al. "Scale-dependent diffusion anisotropy in nanoporous silicon." Scientific Reports 7 (2017): 40207.

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