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Kerfless exfoliated thin crystalline Si wafers with Al metallization layers for solar cells

Published online by Cambridge University Press:  10 November 2015

Raphael Niepelt ,
Jan Hensen ,
Verena Steckenreiter ,
Rolf Brendel  and
Sarah Kajari-Schöder
Raphael Niepelt*
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
Jan Hensen
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
Verena Steckenreiter
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
Rolf Brendel
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany; and Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover, Germany
Sarah Kajari-Schöder
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
*
a)Address all correspondence to this author. e-mail: niepelt@isfh.de
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Abstract

We report on a kerfless exfoliation approach to further reduce the costs of crystalline silicon photovoltaics making use of evaporated Al as a double functional layer. The Al serves as the stress inducing element to drive the exfoliation process and can be maintained as a rear contacting layer in the solar cell after exfoliation. The 50–70 µm thick exfoliated Si layers show effective minority carrier lifetimes around 180 µs with diffusion lengths of 10 times the layer thickness. We analyze the thermo-mechanical properties of the Al layer by x-ray diffraction analysis and investigate its influence on the exfoliation process. We evaluate the approach for the implementation into solar cell production by determining processing limits and estimating cost advantages of a possible solar cell design route. The Al–Si bilayers are mechanically stable under processing conditions and exhibit a moderate cost savings potential of 3–36% compared to other c-Si cell concepts.

Keywords

Six-ray diffraction (XRD)thermal stresses
Type
Invited Feature Paper
Information
Journal of Materials Research , Volume 30 , Issue 21 , 13 November 2015 , pp. 3227 - 3240
Copyright
Copyright © Materials Research Society 2015 

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Footnotes

Contributing Editor: Don W. Shaw

This paper has been selected as an Invited Feature Paper.

References

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