Hopping transport on a fractal: ac conductivity of porous silicon

M. Ben-Chorin, F. Möller, F. Koch, W. Schirmacher, and M. Eberhard
Phys. Rev. B 51, 2199 – Published 15 January 1995
PDFExport Citation

Abstract

We have measured the frequency dependence of the conductivity and the dielectric constant of various samples of porous Si in the regime 1 Hz to 100 kHz at different temperatures. The conductivity data exhibit a strong frequency dependence. When normalized to the dc conductivity, our data obey a universal scaling law, with a well-defined crossover in which the real part of the conductivity σ changes from an ω1/2 dependence to being proportional to ω. We explain this in terms of activated hopping in a fractal network. The low-frequency regime is governed by the fractal properties of porous Si, whereas the high-frequency dispersion comes from a broad distribution of activation energies. Calculations using the effective-medium approximation for activated hopping on a percolating lattice give fair agreement with the data.

  • Received 2 September 1994

DOI:https://doi.org/10.1103/PhysRevB.51.2199

©1995 American Physical Society

Authors & Affiliations

M. Ben-Chorin, F. Möller, and F. Koch

  • Physik-Department E16, Technische Universität München, D-85747 Garching, Germany

W. Schirmacher and M. Eberhard

  • Physik-Department E13, Technische Universität München, D-85747 Garching, Germany

References (Subscription Required)

Click to Expand
Issue

Vol. 51, Iss. 4 — 15 January 1995

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×