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Application of X-ray synchrotron techniques to the characterization of the chemical nature and recombination activity of grown-in and process-induced defects and impurities in solar cells

Published online by Cambridge University Press:  01 February 2011

T. Buonassisi
Affiliation:
Lawrence Berkeley National Laboratory, MS 62-203, 1 Cyclotron Rd., Berkeley CA 94720
O.F. Vyvenko
Affiliation:
Lawrence Berkeley National Laboratory, MS 62-203, 1 Cyclotron Rd., Berkeley CA 94720
A.A. Istratov
Affiliation:
Lawrence Berkeley National Laboratory, MS 62-203, 1 Cyclotron Rd., Berkeley CA 94720
E.R. Weber
Affiliation:
Department of Materials Science and Engineering, University of California, 475 Evans Hall, Berkeley CA 94720
R. Schindler
Affiliation:
Fraunhofer Institute for Solar Energy Systems, Heidenhofstrasse 2, D-79110 Freiburg, Germany
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Abstract

Results of the application of a combination of synchrotron radiation based analytical techniques, X-ray Beam Induced Current (XBIC) and microprobe X-ray Fluorescence (ν-XRF) to the analysis of shunts and lifetime limiting defects in solar cells are reported. XBIC, a new lifetime measurement technique similar to the Laser Beam Induced Current (LBIC) technique, uses a focused X-ray beam to generate minority charge carriers, which are then collected by the p-n junction of the solar cell. The X-ray beam is focused down to a spot size varying from approximately 1×1 νm to 5×5 νm, depending on the settings of focusing mirrors and slits. The sample stage is moved by computer-controlled step motors with sub-micron accuracy. Since the X-ray Beam Induced Current, which characterizes the minority carrier diffusion length in the spot where the X-ray beam hits the sample, and the X-ray Fluorescence signal, which characterizes the chemical nature of the precipitates under the beam, are measured at the same time, the chemical nature of the defects and impurities and their recombination activity can be studied simultaneously, in situ, and with a micron-scale resolution.

We present the results of the applications of these techniques to low lifetime regions in fully processed solar cells. The solar cells were pre-characterized by LBIC and thermography, and regions of interest (containing shunts) were selected. An ν-XRF scan in this area of low lifetime revealed the presence of silver and titanium far from the contact strip, suggesting a process-induced defect.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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References

1. McHugo, S. A., Thompson, A. C., Lamble, G., MacDowell, A., Celestre, R., Padmore, H., Imaizumi, M., Yamaguchi, M., Périchaud, I., Martinuzzi, S., Werner, M., Rinio, M., Möller, H.J., Sopori, B., Hieslmair, H., Flink, C., Istratov, A. A., and Weber, E. R., in Applications of synchrotron radiation techniques to materials science IV, Mini, S. M., Stock, S. R., Perry, D. L., and Terminello, L. J., Editors, p. 297, Mat. Res. Soc., Warrendale (1998).Google Scholar
2. McHugo, S. A., Thompson, A. C., Lamble, G., Flink, C., and Weber, E. R., Physica B 273-274, 371 (1999)Google Scholar
3. McHugo, S. A., Thompson, A. C., Flink, C., Weber, E. R., Lamble, G., Gunion, B., MacDowell, A., Celestre, R., Padmore, H. A., and Hussain, Z., J. Cryst. Growth 210, 395 (2000)Google Scholar
4. Vyvenko, O. F., Buonassisi, T., Istratov, A. A., Hieslmair, H., Thompson, A. C., Schindler, R., and Weber, E. R., J. Appl. Phys. 91, 3614 (2002)Google Scholar
5. Breitenstein, O., Iwig, K., and Konovalov, I., phys. stat. sol. (a) 160, 271 (1997)Google Scholar