Volume 54, Number 2, April 2001
|Page(s)||234 - 240|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||01 December 2003|
Temperature-dependent electrical conduction in porous silicon: Non-Arrhenius behavior
Department of Chemical Engineering, Faculty of Engineering, Hiroshima University
1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan
2 Materials Science & Engineering, Henry Samueli School of Engineering University of California, Irvine, CA92697-2575, USA
Accepted: 13 February 2001
A model for the temperature dependence of electrical conduction in a porous silicon (PS) layer is introduced based on the consideration that the onset of electrical conduction is dependent on the formation of a continuous network of conducting sites extending the entire thickness of a PS layer. At an arbitrary temperature, a PS layer consists of both unblocked and blocked sites (blocking energies are larger than thermal fluctuation energy). The fraction of unblocked sites increases with temperature. At low temperatures () a PS layer is mainly dominated by a continuous network of blocked sites, while discrete unblocked sites do not form any continuous network extending the entire thickness of a PS layer. At medium temperatures () both continuous networks of unblocked and blocked sites appear in a PS layer. And at higher temperatures (), a PS layer is mainly dominated by a continuous network of unblocked sites, while discrete blocked sites do not form any continuous network extending the entire thickness of a PS layer. Contrary to the prevalent views, the overall temperature dependence of the electrical conductivity of a PS is not always Arrhenius: it obeys a Vogel-Tammann-Fulcher (VTF) law at , becomes insulating at , and exhibits the Arrhenius behavior only for . Both T1 and T2 are found to increase with the decrease silicon nanocrytallites sizes. The VTF behavior was derived using the mean-field approximation for Ising model and found to agree with experimental evidences.
PACS: 73.23.-b – Electronic transport in mesoscopic systems / 73.50.-h – Electronic transport phenomena in thin films / 73.61.Tm – Nanocrystalline materials
© EDP Sciences, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.