Electrical conductivity mechanisms in porous silicon

In the present paper the peculiarities of conductivity of porous silicon are studied. For the first time an attempt is made to describe analytically the dependence of porous silicon conductivity on material porosity. It is found that the conductivity is mainly crystalline for porosities much lower than the percolation threshold at 57%, while a fractal behavior is observed at porosities near percolation threshold. For higher values of porosities, the conductivity turns smoothly into a quasi-one-dimensional hopping. The reduction of the electrical current flow channels dimension from 3 to I for lower temperatures, described by the Mott law for amorphous semiconductors, occurs in porous silicon with increasing porosity.