Abstract
Amorphous iron disilicide (a-FeSi ) shows potential as a photovoltaic material due to its bandgap of ∼0.9 eV and high absorption coefficient. We present a detailed characterization of a-FeSi , with particular emphasis on the electrical properties of a-FeSi /c-Si heterostructures, under both dark and illuminated conditions. The samples were prepared on quartz and silicon substrates using RF co-sputtering of an iron/silicon target. Optical transmission spectroscopy was used to confirm the bandgap of the samples. Van der Pauw measurements and currentvoltage analysis techniques were used to determine the carrier type and conduction mechanisms of the samples. The results show that a-FeSi forms a rectifying pn heterojunction on p-type crystalline silicon. The silicide is characterized by very high carrier concentrations, resulting in the depletion region being almost entirely formed within the silicon substrate. Initial JV results suggest carrier recombination within the silicide to be the dominant contribution to the conduction across the junction, with photovoltaic effects having been observed under AM1.5 conditions. © 2012 IOP Publishing Ltd.