XPS study of CZTSSe monograin powders

“Green” Aqueous Synthesis and Advanced Spectral Characterization of Size-Selected Cu2ZnSnS4 Nanocrystal Inks

“…The spectrum of Cu L 3 M 4,5 M 4,5 Auger electrons (Fig. 2e) shows the most intense Cu L 3 M 4,5 M 4,5 ( 1 G) peak at 916.8 eV (in the kinetic energy scale) as well as an Auger parameter of 1849 eV both typical for copper(I) 69,73 thus supporting our above assignment of copper to the Cu(I) state.…”

“…2d). The observed Sn 3d 5/2 peak centered at 486.3 eV and the spin-orbit splitting of 8.5 eV are typical for Sn(IV) 24,43,47,61,67–69,73 . This assignment is supported by an analysis of the Sn M 4,5 N 4,5 N 4,5 Auger electron energy spectrum (Fig.…”

“…This broadening is a result of an additional relaxation path for the L 2 (2p 1/2 ) hole due to L 2 L 3 M 4,5 Coster-Cronig transition, which reduces the lifetime of the hole and broadens the Cu2p 1/2 peak 71 . The positions of peaks, the distance between them (19.9 eV), the absence of an additional contribution at around 934/954 eV, as well as the absence of paramagnetic Cu(II) satellite peaks at ~940–945 eV 72 indicate that copper is present in the sample solely as Cu(I) typically found in CZTS NCs 24,43,47,61,67–69,73 . Nevertheless, as the differences reported in the literature between the positions of Cu(I) and Cu(II) compounds (oxides and chalcogenides) are rather small, we examined additionally with high-resolution XPS spectra the range of the Auger electron peak of copper, which is more sensitive to the chemical surrounding than the XPS peaks.…”

“…2a) shows a characteristic doublet at 1021 eV and 1044 eV with a spin-orbit splitting of 23 eV typical for Zn 2+ in chalcogenide lattices 24,43,47,61,67–69 . The high quality of the fit attests the absence of other forms of Zn(II) in the system under scrutiny.

Figure 2( a – d ) High-resolution XPS spectra in the range of Zn 2p ( a ), S 2p ( b ), Cu 2p ( c ), and Sn 3d ( d ).

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Fill Factor Losses in Cu2ZnSn(SxSe1−x)4 Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

“…Furthermore, a shoulder peak was observed near the Sn 3 d 3/2 peak, which is attributed to the Zn-Auger peak L 3 M 45 M 45 and normally seen in CZTSSe crystals. [ 44 ] This indicates that the CZTSSe phase was only detected after 20 min of sputtering (shorter sputtering was not done)-a sign of secondary phase formation at the back interface. To examine the chemical composition at each sputtered layer, the areas under the curves of Cu 2 p 3/2 , Zn 2 p 3/2 , Sn 3 d 5/2 , and S-Se 2 p were fi tted and calculated by applying Shirley-background subtraction followed by a Lorentzian-Gaussian fi t. Fitted areas were normalized by the relative sensitivity factor of each element and the atomic% of each element was calculated, showing a Zn-and Sn-rich composition (with almost no Cu) at the back interface (Figure 7 f).…”