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
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2023-12-01 |
| Journal | Journal of Phase Equilibria and Diffusion |
| Authors | І. А. Іващенко, В. С. Козак, L. D. Gulay, V. V. Galyan |
| Institutions | Lesya Ukrainka Volyn National University, Cracow University of Technology |
| Citations | 1 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Advanced Semiconductor Platforms
Section titled “Technical Documentation & Analysis: Advanced Semiconductor Platforms”Executive Summary
Section titled “Executive Summary”This research investigates the phase equilibria and crystal structures of complex quaternary chalcogenide-halide compounds (e.g., CuIn2Se3I, CuGa2Te3I), which are classified as defective diamond-like semiconductors (DLS). The findings are crucial for establishing optimal growth conditions for single crystals, a prerequisite for advanced device development.
- Core Achievement: Construction of the isothermal section (770 K) and liquidus surface projection for the Cu2Se-In2Se3-CuI quasi-ternary system, defining primary crystallization regions.
- Key Material Properties: Confirmed congruent melting of the quaternary compound CuIn2Se3I at 1213 K (940 °C) and established its homogeneity region (9 to 15 mol.% CuI).
- Structural Analysis: Determined the crystal structures of CuGa2Te3I and AgGa2Te3Br, confirming tetragonal symmetry (Space Group I-4) and discussing their connection to defective diamond-like structures.
- Future Research Goal: The authors explicitly target growing single crystals of these DLS materials to investigate their semiconducting properties.
- 6CCVD Value Proposition: 6CCVD MPCVD diamond (SCD) provides the ultimate wide-bandgap platform, offering superior thermal conductivity and structural stability compared to traditional semiconductor substrates, ideal for integrating novel DLS thin films or for high-power applications where DLS materials are being explored.
- Customization Advantage: 6CCVD offers custom SCD and PCD substrates with ultra-low surface roughness (Ra < 1nm) and precise metalization schemes necessary for advanced thin-film deposition and device prototyping.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Isothermal Section Temperature | 770 (497) | K (°C) | Temperature for phase equilibrium analysis |
| CuIn2Se3I Melting Point | 1213 (940) | K (°C) | Congruent melting temperature |
| CuIn2Se3I Homogeneity Region | 9 to 15 | mol.% CuI | Within the composition triangle |
| CuGa2Te3I Lattice Parameter (a) | 5.9147(4) | Å | Tetragonal unit cell dimension |
| CuGa2Te3I Lattice Parameter (c) | 11.952(2) | Å | Tetragonal unit cell dimension |
| AgGa2Te3Br Lattice Parameter (a) | 6.2977(3) | Å | Tetragonal unit cell dimension |
| AgGa2Te3Br Lattice Parameter (c) | 11.9473(7) | Å | Tetragonal unit cell dimension |
| Synthesis Purity (Cu, In, Se) | 99.99 - 99.997 | wt.% | High-purity starting materials |
| Ampoule Residual Pressure | 1.33·10-2 | Pa | Vacuum level during sealing |
| Homogenization Annealing Time | 300 | h | Annealing at 770 K (497 °C) |
| Cation:Anion Ratio (DLS) | 3:4 | N/A | Characteristic ratio for cation-deficient compounds |
Key Methodologies
Section titled “Key Methodologies”The investigation relied on high-purity synthesis and rigorous thermal and structural characterization to map the phase diagram:
- Material Preparation: Simple substances (Cu, In, Se) of high purity were used. Cuprous iodide (CuI) was synthesized via the interaction of CuSO4·5H2O with NaI in the presence of SO2.
- Ampoule Synthesis: Prepared weights were sealed in evacuated ampoules (residual pressure 1.33·10-2 Pa) and placed in metal tubes for thermal processing.
- Controlled Thermal Profile: Samples were synthesized in automatic furnaces (“Thermodent”) with precise temperature regulation (± 5 K), following a multi-stage heating and annealing schedule:
- Heating to 670 K (10 K/h rate), followed by 48 h annealing.
- Heating to a maximum of 1070 K, followed by 48 h holding.
- Cooling to 770 K (20 K/h rate).
- Homogenization: Extended annealing at 770 K for 300 h was performed to ensure the equilibrium state of the synthesized alloys.
- Phase Analysis: Differential Thermal Analysis (DTA) and X-ray Diffraction (XRD) using a DRON 4-13 diffractometer (CuKα radiation) were employed to construct the phase diagrams and identify crystalline phases.
- Crystal Structure Determination: Powder diffraction methods and full profile refinement were used to determine the tetragonal crystal structures (Space Group I-4) of the novel quaternary compounds.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The research highlights the ongoing global effort to develop advanced semiconductors, specifically those with defective diamond-like structures. As the ultimate wide-bandgap semiconductor platform, 6CCVD MPCVD diamond is uniquely positioned to support and accelerate this research, offering materials that surpass traditional substrates in thermal, mechanical, and electrical performance.
Applicable Materials
Section titled “Applicable Materials”To replicate or extend this research, particularly for integrating DLS thin films into functional devices, 6CCVD recommends the following materials:
- Optical Grade Single Crystal Diamond (SCD): Required for high-quality epitaxial growth or thin-film deposition of novel DLS materials (like CuIn2Se3I). SCD offers the highest thermal conductivity (up to 2200 W/m·K) and a pristine surface (Ra < 1nm) necessary for minimizing lattice mismatch defects and maximizing device performance.
- Polycrystalline Diamond (PCD) Substrates: Ideal for large-area deposition experiments or as robust heat spreaders for integrated DLS devices. 6CCVD provides PCD wafers up to 125mm in diameter with polishing down to Ra < 5nm.
- Boron-Doped Diamond (BDD): If the DLS research requires an electrically conductive platform or counter-electrode for electrochemical studies, 6CCVD offers heavily doped BDD films and substrates.
Customization Potential
Section titled “Customization Potential”The synthesis of novel quaternary compounds often requires unique substrate preparation and integration steps. 6CCVD’s in-house engineering capabilities directly address these needs:
| Research Requirement | 6CCVD Custom Solution | Technical Specification |
|---|---|---|
| Substrate Size/Shape | Custom dimensions and laser cutting | Plates/wafers up to 125mm (PCD); custom shapes available. |
| Thin-Film Integration | Precise thickness control | SCD/PCD films from 0.1µm up to 500µm. |
| Electrical Contacting | Custom metalization schemes | Internal capability for Au, Pt, Pd, Ti, W, Cu deposition. |
| Surface Quality | Ultra-low roughness for epitaxy | Ra < 1nm (SCD); Ra < 5nm (Inch-size PCD). |
| High-Temperature Processing | Robust substrate material | Diamond substrates maintain integrity under high-temperature DLS synthesis (e.g., 1213 K / 940 °C). |
Engineering Support
Section titled “Engineering Support”The authors’ stated goal is to grow single crystals and investigate the semiconducting properties of these DLS materials. 6CCVD’s in-house PhD team specializes in wide-bandgap semiconductor physics and material integration. We offer consultation services to assist researchers in:
- Selecting the optimal diamond grade (SCD vs. PCD) based on the required thermal and electrical properties for the specific DLS application.
- Designing appropriate metalization stacks (e.g., Ti/Pt/Au) for ohmic or Schottky contacts on DLS films deposited onto diamond.
- Providing high-quality, globally shipped substrates (DDU default, DDP available) to ensure research continuity.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract The quasi-ternary system Cu 2 Se-In 2 Se 3 -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 CuIn 2 Se 3 I 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 CuGa 2 Te 3 I and AgGa 2 Te 3 Br 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 CuGa 2 Te 3 I; a = 6.2977(3) Å, c = 11.9473(7) Å for AgGa 2 Te 3 Br compound, respectively. The connection of their structures with the structures of the defective diamond-like semiconductors has been discussed .