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 co mplicated. In this paper we obtain an analytical expression for the ef fective electrical conductivity of a model simulating porous silicon ( PS). We use the averaging volume method that has proven to be successf ul in treating fluid transport in porous media. The PS model is based on experimental information about this new material's structure and ex perimental data for crystalline Si and hydrogenated a-Si thin films. W ith 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; beyo nd this value, it decreases to zero. The behavior of the effective ele ctrical conductivity may be important for electronic applications of P S.