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Main Title: Annihilation of structural defects in chalcogenide absorber films for high-efficiency solar cells
Author(s): Mainz, Roland
Sanli, Ekin Simsek
Stange, Helena
Azulay, Doron
Brunken, Stephan
Greiner, Dieter
Hajaj, Shir
Heinemann, Marc D.
Kaufmann, Christian A.
Klaus, Manuela
Ramasse, Quentin M.
Rodriguez-Alvarez, Humberto
Weber, Alfons
Balberg, Isaac
Millo, Oded
Aken, Peter A. van
Abou-Ras, Daniel
Type: Article
Language Code: en
Abstract: In polycrystalline semiconductor absorbers for thin-film solar cells, structural defects may enhance electron-hole recombination and hence lower the resulting energy conversion efficiency. To be able to efficiently design and optimize fabrication processes that result in high-quality materials, knowledge of the nature of structural defects as well as their formation and annihilation during film growth is essential. Here we show that in co-evaporated Cu(In,Ga)Se-2 absorber films the density of defects is strongly influenced by the reaction path and substrate temperature during film growth. A combination of high-resolution electron microscopy, atomic force microscopy, scanning tunneling microscopy, and X-ray diffraction shows that Cu(In,Ga)Se-2 absorber films deposited at low temperature without a Cu-rich stage suffer from a high density of - partially electronically active - planar defects in the {112} planes. Real-time X-ray diffraction reveals that these faults are nearly completely annihilated during an intermediate Cu-rich process stage with [Cu]/([In] + [Ga]) > 1. Moreover, correlations between real-time diffraction and fluorescence analysis during Cu-Se deposition reveal that rapid defect annihilation starts shortly before the start of segregation of excess Cu-Se at the surface of the Cu(In,Ga)Se-2 film. The presented results hence provide direct insights into the dynamics of the film-quality-improving mechanism.
Issue Date: 2016
Date Available: 24-Oct-2017
DDC Class: 690 Hausbau, Bauhandwerk
Journal Title: Energy & environmental science
Publisher: Royal Society of Chemistry
Publisher Place: Cambridge
Volume: 9
Issue: 5
Publisher DOI: 10.1039/c6ee00402d
Page Start: 1818
Page End: 1827
EISSN: 1754-5706
ISSN: 1754-5692
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Appears in Collections:FG Metallische Werkstoffe » Publications

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