Lifetime-limiting defects in monocrystalline silicon

Abstract: This thesis discusses studies performed by the author at the Fraunhofer Institute for Solar Energy Systems, ISE in cooperation with the Freiburg Materials Research Center, FMF. The main achievements are:

- A new measurement technique was developed that allows the investigation of the distribution of interstitial oxygen atoms in silicon wafers. The method is based on photoluminescence imaging and the measurement of resistivity changes upon annealing at 450 °C. This results in a high lateral resolution on full samples with reasonable effort. It thereby opens up pathways to improve the understanding of the distribution of impurities during crystal growth. Furthermore, the method can be applied to very thin wafers without loosing precision. It is therefore feasible for typical sample thicknesses in photovoltaic research, where application of infrared absorption spectroscopy becomes problematic.

- An extensive literature review of the broad field of studies of the light-induced degradation caused by boron-oxygen defects is given. The review provides an overview over aspects that were subject of vivid discussions in literature. It reduces the pronounced fragmentation of the scientific discourse in the field by indentifying established and controversial findings in literature.

- Detailed experiments to investigate the activation kinetics of boron-oxygen defects were performed on compensated n-type silicon. The results provide unambiguous confirmation of the strong dependence of the activation rates on the concentration of holes during illumination. This influence was demonstrated to apply to both, the fast and the slow activation processes. This finding indicates the involvement of two holes in both defect state transitions.

- The recombination activity of boron-oxygen defects was investigated in dependence of sample doping and injection conditions. The experiments provide strong evidence that boron-oxygen defects introduce at least two energetic levels in the silicon band gap that interact during recombination

Standort
Deutsche Nationalbibliothek Frankfurt am Main
Umfang
Online-Ressource
Sprache
Englisch
Anmerkungen
Universität Freiburg, Dissertation, 2017

Schlagwort
Silicium
Solarzelle
Gitterbaufehler
Rekombination

Ereignis
Veröffentlichung
(wo)
Freiburg
(wer)
Universität
(wann)
2019
Urheber
Beteiligte Personen und Organisationen

DOI
10.6094/UNIFR/17380
URN
urn:nbn:de:bsz:25-freidok-173802
Rechteinformation
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Letzte Aktualisierung
25.03.2025, 13:51 MEZ

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Entstanden

  • 2019

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