Transport in porous silicon: the pea-pod model

It is shown that there are two routes of electrical transport in luminescent porous silicon. The first is between silicon crystallites and the other is 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' charging energy. The conduction mechanism in the second route is similar to that encountered in hydrogenated amorphous silicon, that is extended-states transport in a disordered semiconductor. The implication of these findings on the prospects of efficient electroluminescence in porous silicon are discussed.