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Wilhelm Warta
Researcher at Fraunhofer Society
Publications - 258
Citations - 21740
Wilhelm Warta is an academic researcher from Fraunhofer Society. The author has contributed to research in topics: Silicon & Carrier lifetime. The author has an hindex of 58, co-authored 258 publications receiving 20808 citations. Previous affiliations of Wilhelm Warta include University of Freiburg & University of Stuttgart.
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Journal ArticleDOI
Predictive Simulation of Doping Processes for Silicon Solar Cells
Jonas Schön,Alireza Abdollahinia,Alireza Abdollahinia,Ralph Müller,Jan Benick,Martin Hermle,Wilhelm Warta,Martin C. Schubert +7 more
TL;DR: In this article, the authors present improvements and calibrations for boron and phosphorus doping models, which allow highly predictive simulations of various doping processes used for solar cells, including oxidation and implantation processes for solar cell applications.
Journal ArticleDOI
Impact of stress on the recombination at metal precipitates in silicon
Paul Gundel,Martin C. Schubert,Friedemann D. Heinz,Wolfram Kwapil,Wilhelm Warta,Gema Martínez-Criado,Manfred Reiche,Eicke R. Weber +7 more
TL;DR: In this paper, the authors investigate the recombination activity of metal precipitates and present a strong positive correlation between their recombination performance and the stress around them, independent of the type of metal forming the precipitate.
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Identification of the most relevant metal impurities in mc n-type silicon for solar cells
Jonas Schön,Florian Schindler,Florian Schindler,Wolfram Kwapil,Wolfram Kwapil,M. Knörlein,Patricia Krenckel,Stephan Riepe,Wilhelm Warta,Martin C. Schubert +9 more
TL;DR: In this article, the authors used Neutron Activation Analysis (NAA) and Inducitvely Coupled Plasma Mass Spectrometry (ICP-MS) to identify the main currently unavoidable metal impurities present in n-type multicrystalline (mc) silicon.
Journal ArticleDOI
High net doping concentration responsible for critical diode breakdown behavior of upgraded metallurgical grade multicrystalline silicon solar cells
TL;DR: In this article, the reverse current flows through many soft breakdown sites at recombination active defects due to the increased net doping concentration in the wafer base of UMG-Si wafers compared to standard multicrystalline silicon.
Proceedings ArticleDOI
Physical mechanisms of breakdown in multicrystalline silicon solar cells
Otwin Breitenstein,Jan Bauer,Jan-Martin Wagner,Horst Blumtritt,Andriy Lotnyk,Martin Kasemann,Wolfram Kwapil,Wilhelm Warta +7 more
TL;DR: In this article, the authors identified at least five different local breakdown mechanisms according to the temperature coefficient (TC) and slope of their characteristics and electroluminescence (EL) under reverse bias.