Regensburg 2000 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 15: Photovoltaik I

HL 15.12: Vortrag

Dienstag, 28. März 2000, 12:15–12:30, H14

ELECTRONIC PROPERTIES OF THIN FILM SILICON — •Rudolf Brüggemann, Jean-Paul Kleider, and Christophe Longeaud — Laboratoire de Genie Electrique de Paris, Supelec, Plateau de Moulon, F-91192 Gif-sur-Yvette Cedex

We have studied the electronic properties of thin film silicon, prepared by various deposition techniques, that are of interest for the application in photovoltaic devices. The films cover the range from amorphous silicon over microcrystalline silicon with nanometer-sized grains to polycrystalline silicon with grain sizes up to 100 nm and were prepared by solid-phase crystallisation (SPC) of amorphous silicon, plasma-enhanced chemical vapour deposition (PECVD) and hot-wire chemical vapour deposition (HWCVD). The undoped thin-film Si samples were characterised with respect to majority and minority carrier mobility-lifetime products from photoconductivity and photocarrier grating (PCG) experiments. We find that the mobility-lifetime products of the microcrystalline silicon samples from several deposition systems are in the range of those of hydrogenated amorphous silicon. The diffusion length of the SPC polycrystalline silicon samples can be much larger than that of the microcrystalline samples. We applied transient photoconductivity (TPC) with a Fourier transform technique and modulated photoconductivity (MPC) to determine the density of gap states. The results show exponentially distributed densities of states in the HWCVD and PECVD microcrystalline silicon and in the SPC polycrystalline silicon.