EFFECTIVE ELECTRICAL-CONDUCTIVITY OF POROUS SILICON - A NOVEL THEORETICAL APPROACH

From a theoretical point of view, linear transport is well understood. However, transport phenomena through porous materials are far more complicated. In this paper we obtain an analytical expression for the effective electrical conductivity of a model simulating porous silicon (PS). We use the averaging volume method that has proven to be successful in treating fluid transport in porous media. The PS model is based on experimental information about this new material's structure and experimental data for crystalline Si and hydrogenated a-Si thin films. With this method we can calculate the bulk and the surface contribution to the effective conductivity. We find that the effective electrical conductivity increases to a maximum value at an optimum porosity; beyond this value, it decreases to zero. The behavior of the effective electrical conductivity may be important for electronic applications of PS.