Piezoelectric nonlinear optic CuGaS2 and CuInS2 crystal structure: Sublattice distortion in AIBIIIC2VI and AIIBIVC2V type chalcopyrites

Abstract

CuGaS2 and CuInS2 are typical AIBIIIC2VI members of the chalcopyrite structure family. The lattice constants of tetragonal CuGaS2 are a = 5.34741 ± 0.00007 and c = 10.47429 ± 0.00006 Å at 298 °K, and of CuInS2 are a = 5.52279 ± 0.00007 and c = 11.13295 ± 0.00022 Å at 298 °K. Both materials have four formulas in a unit cell with space group I 42d. A total of 984 reflections for CuGaS2 and 1413 for CuInS2 were measured with PEXRAD, and the resulting 134 symmetry-independent CuGaS2 and 310 CuInS2 structure factors, in least-squares refinement, led to final agreement factors of 0.029 and 0.038, respectively. Both materials are slightly nonstoichiometric. Final x coordinates are 0.2593 ± 0.0004 for CuGaS2 and 0.2295 ± 0.0004 for CuInS2. As was also found with AgGaS, these values are significantly different from those expected for a geometrically regular B atom tetrahedron. The resulting sublattice distortion is predictable from a linear sum of atomic electronegativities, which is also used to predict the x coordinate and interatomic bond lengths in 17 other AIBIIIC2VI chalcopyrites. The sublattice distortion in AIIBIVC2V chalcopyrites is generally small, but also significant. The experimental Cu–S distance is 2.312 ± 0.001 Å in CuGaS2 and 2.335 ± 0.001 Å in CuInS2, the Ga–S distance is 2.288 ± 0.001, and In–S is 2.464 ± 0.002 Å. The amplitudes of thermal vibration for the A and B atoms in AgGaS2, CuGaS2, and CuInS2 are essentially isotropic, with considerable anisotropy in the C atom motion.

Thermal expansion and structural properties of (CuAlTe2)1–x(CuAlSe2)x solid solutions

“…These values are similar to the values of RMS experimentally determined for the other I-III-VI 2 semiconductors [11]. The results of calculations are also presented in table 1, and they illustrate that Debye temperature rises with the increase of selenium content in the investigated system of solid solutions, and simultaneously, the mean-square dynamic displacements ū 2 decrease.…”

“…This equation does not take into account the sublattice distortion in the I-III-VI 2 chalcopyrites ∆u. ∆u is approximated with an average error of 0.03 Ǻ [11] by the linear sum of electronegativities given by the equation:…”

Crystal structure of copper(I) zinc indium disulfide,(Cu1.02Zn0.11)In0.87S2

“…A twin refinement using the HKLF5 format and three batch scale factors (BASF) which were 0.304(2), 0.308(2) and 0.080(4) confirmed the assumed twin laws and the contribution intensity of each twin or domain component. The resulting chalcopyrite-type structure is very similar to the model found by Abrahams and Bernstein [3] showing a difference in thex-parameter of sulfur representing a smaller tetragonal distortion. Using the chemical composition of the material as constraint in the refinement the site occupancies were determined.…”

Investigation of the size–property relationship in CuInS2quantum dots

“…They can be assigned to the main diffractions (112), (204) and (312) of the tetragonal roquesite structure. 48 The mean particle sizes are 2.9 nm for the feed, 2.8 nm for the coarse and 2.4 nm for the fines fraction. No further diffractions or irregularities were observed in the feed, coarse fraction #1 or fines fraction #2.…”