Phase Equilibria in the Quasi-Ternary System Cu2Se-In2Se3-CuI and the Crystal Structure of the AIBIII2XVI3YVII Compounds, Where AI-Cu, Ag; BIII-Ga; XVI-Cl, Br, I; YVII-S, Se, Te

J. Phase Equilib. Diffus. https://doi.org/10.1007/s11669-023-01073-9 ORIGINAL RESEARCH ARTICLE Phase Equilibria in the Quasi-Ternary System Cu2Se-In2Se3-CuI and the Crystal Structure of the AIBIII2XVI3YVII Compounds, Where AI-Cu, Ag; BIII-Ga; XVI-Cl, Br, I; YVII-S, Se, Te I. A. Ivashchenko1 • V. S. Kozak2 • L. D. Gulay3 • V. V. Galyan3 Submitted: 14 March 2023 / in revised form: 20 October 2023 / Accepted: 14 November 2023  The Author(s) 2023 Abstract The quasi-ternary system Cu2Se-In2Se3-CuI has been investigated by x-ray diffraction and differential thermal analysis. The isothermal section at 770 K and the liquidus surface projection of the system have been built. For the first time, the primary crystallization regions, and the coordinates of the invariant and monovariant equilibria have been determined. In the system, the regions of the solid solutions based on the binary, ternary, and quaternary compounds have been investigated. The formation of the CuIn2Se3I quaternary compound, which melts congruently at 1213 K and has a homogeneity region of 15 and 9 mol.% CuI within the composition triangle has been established. For the first time, the crystal structures of CuGa2Te3I and AgGa2Te3Br compounds have been studied using a powder method. They crystallize in the tetragonal symmetry, Space Group I-4, a = 5.9147(4) Å, c = 11.952(2) Å for CuGa2Te3I; a = 6.2977(3) Å, c = 11.9473(7) Å for AgGa2Te3Br compound, respectively. The connection of their structures with the structures of the defective diamond-like semiconductors has been discussed. Keywords crystal structure  differential thermal analysis  isothermal section  vertical section  x-ray powder diffraction & I. A. Ivashchenko 1 Cracow University of Technology, Cracow, Poland 2 Municipal Institution of Higher Education of the Volyn Oblast Council, Volyn Medical Institute, Lutsk, Ukraine 3 Lesya Ukrainka Volyn National University, Lutsk, Ukraine 1 Introduction The multiphase compositions used in semiconductor devices require the study of phase equilibria in multicomponent systems. Therefore, the Cu2Se-In2Se3-CuI system of the mixed 2-anion chalcogen halide type has been chosen for this study. The quasi-ternary system is formed by binary halides and chalcogenides, which already have vast practical application, in particular AIYVII, where the number of cations is equal to the number of anions (AI-Cu, Ag; YVII-Cl, Br, I), cation excess compound AI2XVI, where AI-Cu, Ag; XVI-S, Se, Te, and cation-defective BIII2XVI3 compounds, where BIII-Ga, In. Since the compounds formed in this system belong to diamond-like semiconductors of the AIBIIIXVI2 and AIYVII types, it will be interesting to investigate the interaction between chalcogenides and halides. The construction of the quasi-binary phase diagrams and liquidus surface projection of the quasi-ternary system allows for determining the regions of the primary crystallization of the compounds and the coordinates of the invariant and monovariant equilibria. Previously, we partially investigated the system Cu2SeIn2Se3-CuI and established a character of the CuIn2Se3I quaternary compound formation in the In2Se3-CuI system.[1] In this work, we present additional results obtained for 3 vertical sections (Cu3InSe3-00 Cu3SeI00 ; 00 Cu3SeI00 CuIn2Se3I; CuIn3Se5-CuIn2Se3I), results for the isothermal section at 770 K and the liquidus surface projection of the quasi-ternary system Cu2Se-In2Se3-CuI. The authors of Ref 2, 3 studied quaternary compounds AIBIII2XVI3YVII, where AI-Cu, Ag; BIII-In; XVI-S, Se, Te; YVII-Cl, Br, I. Phases with structures of the defective zincblende, spinel, and defective NaCl, respectively, were obtained. For example, it was established that the CuIn2Se3I compound crystallizes in the cubic symmetry, Space Group (SG) F-43 m, 123 J. Phase Equilib. Diffus. Fig. 1 Isothermal section of the quasi-ternary system Cu2SeIn2Se3-CuI at 770 K a = 5.781(1) Å.[2] In our work, we decided to investigate the crystal structures of the other quaternary compounds of such type, where BIII-Ga. Some of them were investigated by us previously, like CuGa2S3I,[4] CuGa2Se3I,[4] AgGa2S3Cl,[5] AgGa2Se3Cl,[6] AgGa2Se3Br,[6] AgGa2Te3Cl,[7] AgGa2Te3I.[8] In this work, CuGa2Te3I and AgGa2Te3Br compounds were synthesized to investigate their crystal structures for a better understanding of the nature of the quaternary compounds. Their crystal structures and connection with known defective semiconductors were discussed. 2 Method of Synthesis Simple substances of high purity (Cu-99.99, In-99.99, Se99.997 wt.%) were used to synthesize all alloys of the investigated systems. Cuprous iodide was obtained by the interaction of CuSO45H2O with NaI taken in stoichiometric amounts in the presence of SO2. During the interaction of the solutions, a brown precipitate was formed, 123 which, after passing SO2, turned into a white precipitate of cuprous iodide. The precipitate was filtered on a Buchner funnel and washed with water to remove SO42- ions. It was washed with ethanol and diethyl ether to prevent the product from oxidizing. The ampoules with prepared weights were evacuated to a residual pressure of 1.3310-2 Pa and sealed using a gas-oxygen burner. Before the synthesis, pumped and sealed ampoules were placed in metal tubes. The synthesis was carried out in the automatic furnaces 00 Thermodent00 with a furnace temperature regulation system of ± 5 K. Samples were synthesized as follows: heating to 670 K at a rate of 10 K/h, annealing for 48 h; heating to a maximum temperature of 1070 K, holding for 48 h; cooling to a temperature of 770 K at a rate of 20 K/h and homogenizing annealing was carried out for 300 h to establish the equilibrium state of the synthesized alloys.[1] They were investigated by x-ray diffraction (XRD) method on DRON 4-13 diffractometer (CuKa radiation) and differential thermal analysis (DTA) (00 Thermodent00 H307/1 furnace with a PDA-1 XY-recorder, Pt/Pt-Rh thermocouple). To study the crystal structure of CuGa2Te3I and J. Phase Equilib. Diffus. Fig. 2 The diffractograms of the samples of the system In2Se3-CuI in the region of 50-100 mol.% CuI results of x-ray diffraction analysis (Fig. 1). According to the obtained data, the CuI compound crystallizes in cubic symmetry, SG Fm3m, a = 6.1512(3) Å, which agrees well with Ref 9 (Fig. 2). In the system In2Se3-CuI, the existence of the quaternary compound CuIn2Se3I, which crystallizes in cubic symmetry, is confirmed, SG F43m, a = 5.8012(1) Å, which is in good agreement with Ref 2. Cu2Se is indexed as monoclinic symmetry, SG C2/c, a = 7.1379 Å, b = 12.3823 Å, c = 27.3904 Å, b = 94.308.[10] In2Se3 is indexed as hexagonal symmetry, SG P63/mmc, with unit cell periods a = 4.0242(5) Å, c = 19.251(2) Å, which agrees well with Ref 11. The preliminary results of the xray phase analysis of the Cu2Se-In2Se3 system were described in our previous work.[12-14] The following ternary compounds were established: CuInSe (...truncated)