Microscopic and macroscopic manifestations of percolation transitions in a semiconductor composite

D. Azulay*, O. Millo, E. Savir, J. P. Conde, I. Balberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Using microscopic and macroscopic studies we have derived a comprehensive picture of the relation between the conduction routes and the transport mechanisms in the μc-S:H/a-Si:H composite system. In particular, we have established that in this system the increase of the fractional crystallite phase content, x, brings about two percolation transitions. In the first, at x∼0.3, the transport changes from being via the a-Si:H matrix to taking place via a three-dimensional conducting network consisting of Si microcrystallites that are embedded in the a-Si:H matrix. In the second, at x∼0.7, the dominant transport becomes associated with a two-dimensional network of the disordered silicon tissues that encapsulate the crystallite columns, which form with the increase of x. These two transitions define then three different x regimes which are, from the electrical connectivity point of view, very different from each other. In contrast, the carriers' transport and the carriers' recombination mechanisms are qualitatively quite similar, though quantitatively quite different, in each of the above regimes. Within the framework of this unified picture we are able now to explain various (in some cases contradicting) results that were reported in the literature in which only some aspects, applicable to limited x regimes, have been reported. In turn, the present work brings to light the richness of mechanisms and phenomena that are to be expected in semiconductor composites in comparison with their metal-insulator counterparts.

Original languageAmerican English
Article number245312
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number24
StatePublished - 10 Dec 2009


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