Characterization of CuInS₂‐Cu₂ZnSnS₄ crystals grown from the melt

Abstract

Cu2(2.00‐x)((2In)y (ZnSn)(1.00‐y))x S4 crystals were grown from the melt. 23 samples with different x and y values were synthesized by heating constituent elementary Cu, In, S and Zn‐Sn alloy at 1,250 °C for 10 hours in each evacuated fused‐quartz ampule. All samples were characterized by powder X‐ray diffraction analysis. Two peaks are seen at the 112 diffraction positions in 0.3 ≤ y ≤ 0.9. The FWHM of the 112 diffraction peak broadened in 0.2 ≤ y ≤ 0.7. Lattice constants were obtained by Rietveld method using two tetragonal structure models simultaneously in the refinement. Both a and c obtained as CuInS2 phase changed almost linearly in y ≥ 0.7; therefore the existence of CuInS2 phase solid solution containing Zn and Sn was indicated in this region. The miscibility gap was also suggested as the region of 0.2 ≤ y ≤ 0.7 in our results because of the shape and the broadening of the 112 diffraction peaks. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Crystallographic and optical properties of CuInS2‐Cu2ZnSnS4 crystals

“…Applying two‐curve Gaussian function, peaks at about 28.26(3)° were derived in the range of 0.32 ≤ x ≤ 0.66. This peak was also observed in our previous report . Actually, we found small shoulders at this position in patterns of x = 0.78 and 0.85, but they were too small to evaluate.…”

“…The Rietveld method was applied to derive the lattice constants. The model and the model were used for CuInS 2 phase and Cu 2 ZnSnS 4 phase, respectively . The models were used separately or simultaneously, to obtain suitable results.…”

“…The alloy was prepared from Cu, Zn (5N) and Sn (5N). Melt growth was carried out by the same procedure as in our previous report .…”

“…The aim of this study is to evaluate how much we can substitute the indium atom for zinc and tin atoms in CuInS 2 ‐Cu 2 ZnSnS 4 system. We previously reported crystallographic characterization of CuInS 2 ‐Cu 2 ZnSnS 4 crystals grown from the melt using elemental Cu, In, S, and Zn‐Sn alloy as source materials . However, we could not evaluate the composition dependence precisely since segregation in micro size were observed in the kesterite side.…”