HOPPING TRANSPORT ON A FRACTAL - AC CONDUCTIVITY OF POROUS SILICON

被引：182

作者：

BENCHORIN, M ^{[1
]}

MOLLER, F ^{[1
]}

KOCH, F ^{[1
]}

SCHIRMACHER, W ^{[1
]}

EBERHARD, M ^{[1
]}

机构：

[1] TECH UNIV MUNICH, DEPT PHYS E13, D-85747 GARCHING, GERMANY

来源：

PHYSICAL REVIEW B | 1995年 / 51卷 / 04期

关键词：

D O I：

10.1103/PhysRevB.51.2199

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

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 changes from an 1/2 dependence to being proportional to. 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. © 1995 The American Physical Society.

引用

页码：2199 / 2213

页数：15

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