Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.69: Poster
Thursday, March 17, 2011, 18:00–21:00, P4
Electroluminescence of Thin Film Silicon Solar Cells — •Viola Mönkemöller1, Matthias Niederkrüger2, Helmut Stiebig2, and Ulrich Heinzmann1 — 1Molecular and Surface Physics, Bielefeld University — 2Malibu GmbH & Co. KG, Bielefeld
Electroluminescence (EL) and Dark-Lock-In-Thermography (DLIT) are commonly used methods to characterize crystalline silicon solar modules.
We have applied these methods to analyze thin-film silicon-PV-mini-modules based on amorphous silicon (a-Si) and microcrystalline silicon (µc-Si).
DLIT shows the heat dissipation of the solar cell which originates mainly from the ohmic losses in the Transparent Conductive Oxide (TCO). Defects e.g. electrical short cuts of the cell (shunts) provide a large DLIT signal, due to the high temperature caused by the increased current. In contrast EL shows effects of the semiconductor material. Shunts caused by dust particles in the thin film appear as dark lateral spots since less luminescent recombination takes place.
Furthermore EL allows the distinguishing between a-Si and µc-Si. The different semiconductor band gaps lead to different emission spectra (λµ c−Si>λa−Si). Using adequate filters this behavior leads to the analysis of the individual diodes of tandem modules.
In general EL and DLIT show a similar image of a systematic signal distribution. This effect results from the inhomogeneous voltage and current distribution across the cells in the semiconductor and TCO which is caused by the integrated series connection.