Transport in porous silicon: the pea-pod model

It is shown that there are two routes of electrical transport in luminescen t porous silicon. The first is between silicon crystallites and the other i s through a disordered silicon compound tissue that wraps the crystallites. The conduction mechanism in the first route is similar to that encountered in granular metals, that is tunnelling dominated by the crystallites' char ging energy. The conduction mechanism in the second route is similar to tha t encountered in hydrogenated amorphous silicon, that is extended-states tr ansport in a disordered semiconductor. The implication of these findings on the prospects of efficient electroluminescence in porous silicon are discu ssed.