Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 71: Energy materials: Silicon-based photovoltaics
HL 71.7: Vortrag
Mittwoch, 2. April 2014, 16:30–16:45, POT 151
Formation of near junction and bulk traps in crystalline silicon solar cells — •Teimuraz Mchedlidze1, Christian Möller2, Kevin Lauer2, and Jörg Weber1 — 1Technische Universität Dresden, 01062 Dresden, Germany — 2CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH, Konrad-Zuse-Str. 14, 99099 Erfurt, Germany
Utilization of low quality feedstock for Si crystal growth was acknowledged as a valuable strategy for further price reduction of solar cell production. However, this strategy requires correct determination of the acceptable limits for the feedstock cleanness and relevant tailoring of the solar cell fabrication process. Recently we reported on influence of the fabrication steps on the bulk lifetime in the wafers produced from the various feedstock materials [1]. Deep traps of majority carriers were detected in the similar samples in near to the junction volume (NJV) using mesa-structured n+p-junctions prepared from the processed Si solar cells by deep level transient spectroscopy (DLTS) [2]. In this report we compare results from lifetime measurement and from DLTS for various quality crystals at various stages of solar cell fabrication process. Apparently, the NJV traps differ from those formed in the wafer bulk. However, in the both cases the trap densities correlate with the total content of iron in the crystals. The analyses of our results allow suggesting changes to the solar cell fabrication processes minimizing the influence of iron contamination.
[1] K. Layer, et al., Energy Proc., 38, 589 (2013) [2] T. Mchedlidze, et al., Appl. Phys. Lett., 103, 013901 (2013)