Investigation of Defects in Solar Cells and Wafers by Means of Magnetic Measurements

Abstract:

Elaborated characterization tools play an important role for the further improvement of solar material and the development of solar cells. Besides the huge variety of highly advanced methods mainly based on optical and electrical measurements, the direct measurement of surface currents by the detection of their induced magnetic fields has gained less attention. The novel method current-analysis-by-inductive-coils (CAIC) based on an inductive coil detector and is reviewed and compared with already established methods, which are light-beam-induced-current (LBIC) and dark-lock-in-thermography (LIT). The detector reveals complementary information at high resolution. The LIT measurements depicted shunting defects in forward and reverse current. Because of the high spatial resolution of the CAIC measurement technique it was determinable that in some cases the positions of current sinks in the CAIC maps are not corresponding with the microstructure. The analyses of the superpositions reveals macroscopic precipitates like SiC and Si₃N₄ filaments and clusters as an origin of some of the shunts.

• Periodical: Solid State Phenomena (Volumes 178-179)
• Pages: 331-340
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.178-179.331
• Online since: August 2011
• Authors: Rajko Buchwald, Stefan Köstner, Felix Dreckschmidt, H.J. Möller
• Keywords: Current, Current Distribution, Current Loss, Defect, Electrical Loss, Grain Boundary, Magnetic Field Distribution, Magnetic Measurement, Multicrystalline Silicon, Shunt

References

[1] R. Buchwald, Optoelektrische Magnetfelduntersuchungen an Solarsilizium, PhD thesis, TU Bergakademie Freiberg, Freiberg, Germany, (2010).

[2] R. Buchwald, W. Skorupa, H.J. Möller, The investigation of the shunting behavior of wafer and solar cells produced from different silicon feedstock materials, proceedings 22nd European Photovoltaic Solar Energy Conference, Milano, Italy, (2007).

[3] F. J. Roth, N.G. Sepulveda, J.P. Jr. Wikswo, Using a magnetometer to image a two-dimensional current distribution, Journal of Applied Physics, 65 (1989) 361-72.

DOI: 10.1063/1.342549

[4] O. Breitenstein, J.P. Rakotoniaina, M.H. Al Rifai, M. Werner, Shunt types in crystalline silicon solar cells, Progress in photovoltaics, 2004, 12, 529-538.

DOI: 10.1002/pip.544

[5] J. Bauer, Charakterisierung von Silicumkarbid und Siliciumnitridpartikeln in blockgegossenem Silicium für Solarzellen, Diplomarbeit, Martin-Luther-University Halle-Wittenberg, (2006).

[6] J. Bauer, O. Breitenstein, A. Lotnyk, H. Blumtritt, Investigations on different types of filaments in multi-crystalline silicon for solar cells, 22nd European Photovoltaic Solar Energy Conference, Milano, Italy, (2007).

DOI: 10.1016/j.solmat.2008.04.016