Abstract
We have investigated the high-pressure structural and vibrational behavior of the disordered kesterite-type Cu2ZnSnS4 compound at ambient temperature. Our experimental and theoretical investigations have revealed a clear structural transition to a GeSb-type phase close to 15 GPa, a tetragonally distorted variant of the NaCl-type phase. The latter transformation is accompanied by a cationic coordination increase from fourfold to sixfold with respect to the sulfur anions. In addition, a change in the compressibility rate was detected at about 8 GPa within the pressure stability range of the disordered kesterite-type phase. Upon decompression, a disordered zinc blende/sphalerite structure is recovered. We discuss our findings in close conjunction with our recent high-pressure work on the ordered Cu2ZnSnS4 modification.
Highlights
The quaternary semiconductor C u2ZnSnS4 has attracted considerable attention in recent years due to its potential use as a solar absorber [1, 2]
C u2ZnSnS4 adopts the ordered kesterite-type (KS) structure at ambient conditions (SG I 4, Z = 2, Fig. 1) [7, 8]. This phase is derived from the wellknown zinc blende (ZB)/sphalerite-type structure (SG F 4 2 m, Z = 4) by doubling the respective c-unit-cell parameter, resulting from the alternating cationic arrangement of Cu/ Sn and Cu/Zn layers separated by sulfur anions [9]
The most common type of disorder is associated with the mutual anti-site exchange of the C u+ and Zn2+ cations within the z = 1/4 and z = 3/4 layers, which results in a disordered kesterite-type structural configuration (DKS) with slightly higher symmetry compared to KS (SG I 4 2 m, Z = 2, Fig. 1)
Summary
The quaternary semiconductor C u2ZnSnS4 has attracted considerable attention in recent years due to its potential use as a solar absorber [1, 2]. The most common type of disorder is associated with the mutual anti-site exchange of the C u+ and Zn2+ cations within the z = 1/4 and z = 3/4 layers, which results in a disordered kesterite-type structural configuration (DKS) with slightly higher symmetry compared to KS (SG I 4 2 m, Z = 2, Fig. 1). This compressibility change is reflected mainly in the pressure-induced behavior of the a/c axial ratio (i.e., the a- and c-axis exhibit similar compressibilities) above 8 GPa, stemming most likely from the expansion of the Sn–S bond length beyond that pressure The latter effects are common in both the KS and DKS C u2ZnSnS4 configurations. A closer inspection of the KS compressibility behavior, revealed clear discontinuities in the compressibility of the tetragonal KS a- and c-axis close to 6–8 GPa, whereas no visible effect was detected in the KS volume [20] Such behavior is known to reflect (subtle) structural-related transitions in materials [21–23]. The most striking result, came from the close inspection of the DKS compressibility behavior; the latter revealed certain
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
