Berlin 2012 – wissenschaftliches Programm
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MI: Fachverband Mikrosonden
MI 8: Poster – Microanalysis and microscopy
MI 8.8: Poster
Mittwoch, 28. März 2012, 15:00–17:30, Poster E
Cross-Section STEM Study of Bonding Concepts for Solar Cells — •Dietrich Häußler1, Mert Kurttepeli1, Stephanie Essig2, Karen Derendorf2, Frank Dimroth2, and Wolfgang Jäger1 — 1Microanalysis of Materials, Christian-Albrechts-University Kiel, 24143 Kiel, Germany — 2Fraunhofer Institute for Solar Energy Systems ISE, 79110 Freiburg, Germany
Crystalline silicon based multi-junction solar cells are a promising way to circumvent the conversion efficiency limits of conventional single-junction photovoltaic cells. In GaInP/GaAs/Si multi-junction solar cells, the visible and near infrared wavelength range of the solar spectrum is converted more efficiently when compared to solar cells produced conventionally.
As a decisive step of the technology a bonding process is aimed in which a GaInP/GaAs sub-cell is contacted with a Si substrate. The interface between GaAs and Si is of great importance for the total efficiency of this multi-junction cell.
Cross-section TEM samples are prepared from two types of GaInP/GaAs/Si multi-junction solar cell specimens. In order to investigate the bonding concepts, between the GaAs middle-cell and the Si bottom-cell, in the vicinity of the bonding interface, elemental distributions have been analyzed using STEM / EDXS and pictured using spectra and elemental maps. With the help of HRTEM micrographs an amorphous layer has been detected in the samples and gauged with high accuracy.