c-Si Defect Diagnostics

Fraunhofer Center for Silicon Photovoltaics CSP

© Fraunhofer CSP

Innovative photovoltaic products shall exhibit a high efficiency and a long lifetime. We offer broad facilities of test and analysis possibilities, ranging from applications to solar modules, module components or solar cells. This approach of multi-scale analysis enables us to develop and perform fast industry-related test procedures for our customers to support their material, device and quality advancements. Analytical identified physical or chemical root causes of failures are used for the development of specific accelerated test methods for industrial usage.
Furthermore we characterize with our customers new cell- and module-concepts in terms of their microstructure, composition and local electrical properties, to achieve more efficient, durable and competitive future technologies.

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Topics

Development of accelerated testing methods: PID-solar cell test (without lamination)

A PID-test has been developed, which avoids necessity of modules production and climatic chambers. The solar cells can be directly tested regarding their PID susceptibility.
This rapid test setup, which is patent-registered, enables a quantitative PID-test and also a simple preparation of degraded solar cells surfaces, which is necessary for further analytic researches of the PID-mechanism.

V. Naumann et al., Solar Energy Materials and Solar Cells 120 (2014) 383-389

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Component diagnostic: Evaluation, defect enlightenment and development of solution strategies for solar cell and – module defects

Root causes of defects in solar modules or cells can often be traced back to processes or structures on the microscopic scale. Industry-related quality tests are less suitable for their enlightenment. We use industry-related methods to locate and characterize defect positions scaling from a solar module to microscopic small structure. Customer specific root cause and solution proposals for defect avoidance are worked out. A clear advantage is the correlative analysis of structural-chemical, electrical and thermal information of characteristic defect positions.

S. Großer et al., Energy Proceedia, 55 (2014) 451-455

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High-resolution analysis: microstructure, composition and local electric properties

New and innovative solar cell concepts (e.g. PERC solar cells) enable higher efficiencies and quality. For characterization and evaluation of small structures, we use modern preparation- and high-resolution analysis techniques.    
These methods generate information of local structural, chemical and also electrical properties. Thereby we support our customers in research and development, quality assurance, as well as by identification of potential defects. In close collaboration customer-specific techniques and solutions are developed and optimized.

S. Großer et al., Energy Proceedia, 27 (2012) 7-12

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Equipment

  • Metallography, ion and laser beam assisted sample preparation tools
  • ns laser structuring (1064 nm, 566 nm, 355 nm)
  • inkjet printing
  • Microscopy (optical, NIR, module microscopy)
  • Electroluminescence Microscopy (EL, µEL)
  • Lock-in Thermography
  • Laser Scanning Microscopy
  • Analytical scanning electron microscopy (SEM) with EDX, EBSD, EBIC
  • Transmission electron microscopy (TEM) with EDX
  • Focused ion beam (FIB)
  • Time of flight secondary ion mass spectrometry (ToF-SIMS)
  • X-ray photo electron spectroscopy (XPS)
  • Scanning probe microscopy (AFM/SPM)
  • Electrical micro probe characterization
  • Scanning acoustic microscopy (SAM)

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Publications

  • Naumann, V.; Lausch, D.; Hähnel, A.; Breitenstein, O.; Hagendorf, C.: "2D-extended defects in silicon cause shunting of Si-solar cells", physica status solidi (c) 12, No. 8 (2015) 1103–1107

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  • Großer, S.; Gläser, M.; Brzuska, C.; Tänzer, T.; Schippel, F. & Hagendorf, C.: High-resolution optical and electro-optical microscopy for PV-modules; Energy Procedia, 55 (2014) 451-455
  • Großer, S.; Mayerhofer, R. & Theobald, J.: Microstructure study of laser-opened rear contacts on PERC solar cells; 29th European Photovoltaic Solar Energy Conference, (2014) 1395-1398
  • Naumann, V.; Geppert, T.; Großer, S.; Wichmann, D.; Krokoszinski, H.-J.; Werner, M. & Hagendorf, C.: Potential-Induced Degradation at Interdigitated Back Contact Solar Cells; Energy Procedia, 55 (2014) 498-503
  • Theobald, J.; Hendel, R. & Großer, S.: Laser ablation on modern solar cells. pv magazine, 09 (2014) 80-83
  • Tänzer, T.; Naumann, V.; Großer, S. & Hagendorf, C.: Sheet Resistance Measurements of Highly Resistive Interfacial Layers in Photovoltaic TCO Thin Films; 29th European Photovoltaic Solar Energy Conference, (2014) 1759-1762
  • Naumann, V.; Lausch, D.; Hähnel, A.; Bauer, J.; Breitenstein, O.; Graff, A.; Werner, M.; Swatek, S.; Großer, S.; Bagdahn, J.; Hagendorf, C.: Explanation of potential-induced degradation of the shunting type by Na decoration of stacking faults in Si solar cells.; Solar Energy Materials and Solar Cells 120 (2014) 383-389

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  • Naumann, V.; Lausch, D.; Graff, A.; Werner, M.; Swatek, S.; Bauer, J.; Hähnel, A.; Breitenstein, O.; Großer, S.; Bagdahn, J.; Hagendorf, C.: The role of stacking faults for the formation of shunts during potential-induced degradation of crystalline Si solar cells, Physica status solidi (RRL) - Rapid Research Letters 7 (2013) 315-318
  • Theobald, J.; Mayerhofer, R.; Großer, S.; Harney, R.; Schneider, A.: Extended study on short pulse laser ablation of dielectric layers with UV and VIS laser wavelength and pulse durations from fs to ns, 28th European Photovoltaic Solar Energy Conference and Exhibition, WIP, München (2013) 1231-1235

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  • Bakowskie, R.; Kesser, G.; Richter, R.; Lausch, D.; Eidner, A.; Clemens, P.; Petter, K.: Fast method to determine the structural defect density of 156 x 156 mm² Mc-Si wafers. Energy Procedia 27 (2012) 179-184; 651/2012
  • Bauer, J.; Lausch, D.; Blumtritt, H.; Zakharov, N.; Breitenstein, O.: Avalanche breakdown in multicrystalline solar cells due to preferred phosphorous diffusion at extended defects., Progress in Photovoltaics Research and Applications, 21, 7 (2012) 1444-1453; 279/2012
  • Bauer, J.; Naumann, V.; Großer, S.; Hagendorf, C.; Schütze, M.; Breitenstein, O.: On the mechanism of potential-induced degradation in crystalline silicon solar cells, Physica status solidi (RRL) - Rapid Research Letters 6 (2012) 331-333; 278/2013
  • Bauer, J.; Naumann, V.; Großer, S.; Hagendorf, C.; Schütze, M.; Breitenstein, O.: On the mechanism of potential-induced degradation in crystalline silicon solar cells, Physica Status Solidi - Rapid Research Letters (RRL) 6 (2012) 331-333; 278/2013
  • Großer, S.; Lausch, D.; Werner, M.; Swatek, S.; Mergner, M.; Naumann, V.; Hagendorf, C.: Shunt analysis in solar cells - electro-optical classification and high resolution defect diagnostics. In Proc. of 2nd International Conference on Crystalline Silicon Photovoltaics SiliconPV 2012, Volume 27; Poortmans, J.; Glunz, S.; Aberle, A.; Brendel, R.; Cuevas, A.; Hahn,G.; Sinton, R.; Weeber, A. Eds.; Energy Procidia Elsevier München, Berlin (2012) 7-12; 650/2012
  • Naumann, V.; Hagendorf, C.; Großer, S.; Werner, M.; Bagdahn, J.: Micro structural root cause analysis of potential induced degradation in c-Si solar cells. In Proc. of 2nd International Conference on Crystalline Silicon Photovoltaics SiliconPV 2012, , Volume 27; Poortmans, J.; Glunz, S.; Aberle, A.; Brendel, R.; Cuevas, A.; Hahn, G.; Sinton, R.; Weeber, A.; Energy Procedia Elsevier Ltd. (2012) 1-6; 624/2012

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  • Naumann, V.; Hagendorf, C.; Werner, M.; Henke, B.; Schmidt, C.; Nekarda, J.-F.; Bagdahn, J.: Local electronic properties and microstructure of individual laser-fired contacts. In Proc. of 24th European Photovoltaic Solar Energy Conference and Exhibition, WIP, München (2009) 2180 - 2184; 838/2012

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