AC conductivity of porous silicon: A fractal and surface transport mechanism?

G. Di Francia, V. La Ferrara, P. Maddalena, D. Ninno, L.P. Odierna, V. Cataudella

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In this paper we report on the frequency dependence of the AC conductivity of porous silicon in the range 10 Hz-100 kHz. Two types of testing devices have been fabricated on three different series of samples formed electrochemically using as a starting material p-type, n--type and n+-type silicon substrates. For frequencies less than 20-40 kHz the conductivity is found to follow a sublinear frequency dependence. This behaviour is typical of a carrier transport mechanism determined by an anomalous diffusion process. At higher frequencies we find that surface states influence the transport mechanism. This suggests a double-channel transport mechanism: one related to porous-silicon «volume» properties and the other more connected to the «surface» itself.
Original languageEnglish
Pages (from-to)1187 - 1196
Number of pages10
JournalNuovo Cimento della Societa Italiana di Fisica D - Condensed Matter, Atomic, Molecular and Chemical Physics, Biophysics
Issue number10
Publication statusPublished - 1996


All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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