Composite structures of polyaniline and mesoporous silicon: Electrochemistry, optical and transport properties

Composite structures of p-type mesoporous silicon and polyaniline have been fabricated by a one-step electrochemical polymerization process. The composite structure shows good conduction properties and new, intense photoluminescence emission bands that are assigned to polyaniline that penetrates and fulfills the entire volume of the porous silicon matrix quite uniformly. We have found that at room temperature, the reverse bias conductivity of the composite structure is related to transport through the polyaniline network, giving rise to a 5 orders of magnitude larger current relative to that of a reference porous silicon matrix. At low temperatures, the current at both polarities of the bias voltage is carried in the polyaniline network and is related to variable range hopping in three dimensions.