Microsecond minority carrier lifetimes in HWCVD-grown films and implications for thin film solar cells

Abstract

We determine the minority carrier lifetimes of nearly intrinsic Si films 1.5–15 μm thick grown by HWCVD at 300 °C on Si (100) and large-grained polycrystalline templates formed by selective nucleation and solid-phase epitaxy (SNSPE) using resonant-coupled photoconductive decay (RCPCD). Although the microstructure of these films is mostly microcrystalline, minority carrier lifetimes for films on Si (100) range from 5.7 to 14.8 μs while those for films on SNSPE templates range from 5.9 to 19.3 μs. Residual nickel present in the SNSPE templates may contribute a recombination center but does not significantly decrease the lifetime of films grown on SNSPE templates, making the growth of epitaxial layers by HWCVD on SNSPE templates a viable design for thin-film photovoltaics.

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