Details
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | 40207 |
| Fachzeitschrift | Scientific Reports |
| Jahrgang | 7 |
| Publikationsstatus | Veröffentlicht - 20 Jan. 2017 |
Abstract
Nanoporous silicon produced by electrochemical etching of highly B-doped p-type silicon wafers can be prepared with tubular pores imbedded in a silicon matrix. Such materials have found many technological applications and provide a useful model system for studying phase transitions under confinement. This paper reports a joint experimental and simulation study of diffusion in such materials, covering displacements from molecular dimensions up to tens of micrometers with carefully selected probe molecules. In addition 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 experimental evidence from these studies is confirmed by molecular 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 topology determined by electron tomography.
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in: Scientific Reports, Jahrgang 7, 40207, 20.01.2017.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Scale-dependent diffusion anisotropy in nanoporous silicon
AU - Kondrashova, Daria
AU - Lauerer, Alexander
AU - Mehlhorn, Dirk
AU - Jobic, Hervé
AU - Feldhoff, Armin
AU - Thommes, Matthias
AU - Chakraborty, Dipanjan
AU - Gommes, Cedric
AU - Zecevic, Jovana
AU - De Jongh, Petra
AU - Bunde, Armin
AU - Kärger, Jörg
AU - Valiullin, Rustem
N1 - Funding information: Financial Support by DFG (BU 534/22, KA 953/30), Universität Leipzig within the program of Open Access Publishing, and IUPAC (#2015-002-2-100) is gratefully acknowledged. The QENS measurements were performed at the Institut Laue-Langevin, Grenoble, France, using the IN5 spectrometer, with the help of Dr. J. Ollivier. Stimulating discussions with Jürgen Caro, Hannover, Klaus Kroy, Leipzig, Peter Monson, Amherst, MA, and Douglas M. Ruthven, Orono, ME, are highly appreciated.
PY - 2017/1/20
Y1 - 2017/1/20
N2 - Nanoporous silicon produced by electrochemical etching of highly B-doped p-type silicon wafers can be prepared with tubular pores imbedded in a silicon matrix. Such materials have found many technological applications and provide a useful model system for studying phase transitions under confinement. This paper reports a joint experimental and simulation study of diffusion in such materials, covering displacements from molecular dimensions up to tens of micrometers with carefully selected probe molecules. In addition 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 experimental evidence from these studies is confirmed by molecular 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 topology determined by electron tomography.
AB - Nanoporous silicon produced by electrochemical etching of highly B-doped p-type silicon wafers can be prepared with tubular pores imbedded in a silicon matrix. Such materials have found many technological applications and provide a useful model system for studying phase transitions under confinement. This paper reports a joint experimental and simulation study of diffusion in such materials, covering displacements from molecular dimensions up to tens of micrometers with carefully selected probe molecules. In addition 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 experimental evidence from these studies is confirmed by molecular 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 topology determined by electron tomography.
UR - http://www.scopus.com/inward/record.url?scp=85010038841&partnerID=8YFLogxK
U2 - 10.1038/srep40207
DO - 10.1038/srep40207
M3 - Article
C2 - 28106047
AN - SCOPUS:85010038841
VL - 7
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
M1 - 40207
ER -