Evaluation of defect formation in chalcopyrite compounds under Cu-poor conditions by advanced structural and vibrational analyses. (15th January 2022)

• Record Type: Journal Article
• Authors: Guc, Maxim; Bailo, Eduard; Fonoll-Rubio, Robert; Atlan, Fabien; Placidi, Marcel; Jackson, Philip; Hariskos, Dimitrios; Alcobe, Xavier; Pistor, Paul; Becerril-Romero, Ignacio; Perez-Rodriguez, Alejandro; Ramos, Francisco; Izquierdo-Roca, Victor
• Is Part Of: Acta materialia. Volume 223(2022)
• Publication Date: 2022-01-15
• Subjects: CIGSe -- Raman spectroscopy -- X-ray diffraction -- Defects -- Phase composition; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.117507
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Cu-poor compositions are key for obtaining high efficiency Cu(In, Ga)Se2 (CIGSe) devices. These conditions lead to Cu deficit accommodation mechanisms like the formation of Cu-related defects in the CIGSe crystal structure or of ordered vacancy compound. However, the origin of the benefits of Cu-poor compositions is still under discussion since these mechanisms are difficult to detect and characterize. In this work, a high precision Raman spectroscopy and X-ray diffraction analysis on a compositionally-graded CISe sample ([C u ]/[In] ratios from 0.48 to 1.03) allows us to shed light on this topic by reporting the detection of a "defective chalcopyrite phase" in the slightly Cu-poor compositional regime that may play a critical role, rather than other previously discussed mechanisms, on device performance. This phase is mainly characterized by the formation of a specific defect in the CISe structure which also contributes to appearance of a Raman peak at 230 cm −1 . Finally, the analysis of high efficiency (> 18%) CIGSe solar cells and the extrapolation of the results on defect formation obtained for CISe, suggest a possible impact of the defective chalcopyrite phase on the open circuit voltage of the devices, and opens a possible way to further investigate and develop the chalcopyrite based technologies. Graphical abstract: Image, graphical abstract