Porous silicon as a near-ideal disordered semiconductor

From the temperature dependence of the dark conductivity in porous silicon materials we find activation energies which are larger than half of the optical bandgap. The phototransport properties indicate a continuous conduction path through the tetrahedrally distorted shell of the links which form the porous silicon coral-like network. The results are interpreted in terms of a mobility gap which is due to disorder in the tetrahedral covalent network.