Defect spectroscopy on Cu(In,Ga)(S,Se) 2 -based heterojunction solar cells: role of the damp-heat treatment

The changes of defect characteristics induced by accelerated lifetime tests on solar cells of the heterostructure ZnO/CdS/Cu(In,Ga)(S,Se)2/Mo are investigated. The fill factor and open-circuit voltage of non-encapsulated test cells are reduced after prolonged damp-heat treatment in the laboratory, leading to a reduced energy conversion efficiency. We subject non-encapsulated test cells to damp-heat exposure at 85C ambient temperature and 85% relative humidity for various time periods (6h-438h). We apply temperature-dependent capacitance-voltage measurements, admittance spectroscopy, and deep-level transient spectroscopy. We observe the presence of electronic defect states which showed an increasing activation energy due to damp-heat exposure. We conclude that the response originates from an energetically continuous distribution of defect states in the vicinity of the CdS/chalcopyrite interface. The increase in activation energy indicates a reduced band bending at the Cu(In,Ga)(S,Se)2 surface. We observe changes in the bulk defect spectra due to the damp-heat treatment as well.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Oldenburg

Year

2002

Author dc:creator

• Deibel, Carsten

• [Keine Schlagwörter von Autor/in vergeben.]

Repository record source_url

http://oops.uni-oldenburg.de/213

OAI identifier oai:identifier

oai:oops.uni-oldenburg.de:213