Rare-earth metal catalysts for high-pressure synthesis of rare diamonds
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-04-19 |
| Journal | Scientific Reports |
| Authors | Yuri N. Palyanov, Yuri M. Borzdov, Igor N. Kupriyanov, Alexander F. Khohkhryakov, Denis V. Nechaev |
| Institutions | V.S. Sobolev Institute of Geology and Mineralogy |
| Citations | 9 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Rare-Earth Catalyzed Diamond Synthesis
Section titled âTechnical Documentation & Analysis: Rare-Earth Catalyzed Diamond SynthesisâThis document analyzes the research on Rare-Earth Metal (REM) catalyzed High-Pressure High-Temperature (HPHT) diamond synthesis, focusing on the production of high-purity, nitrogen-free diamond doped with Group IV impurity-vacancy color centers (SiV, GeV, SnV). This research directly aligns with 6CCVDâs core mission to supply advanced Single Crystal Diamond (SCD) and Polycrystalline Diamond (PCD) materials for quantum and high-technology applications.
Executive Summary
Section titled âExecutive Summaryâ- Novel Catalysis: The study successfully established 15 Rare Earth Metals (REM) as effective solvent-catalysts for diamond synthesis under HPHT conditions (7.8 GPa, 1800-2100 °C).
- High Purity Achievement: REMs act as efficient nitrogen getters, enabling the synthesis of high-purity, nitrogen-free Type II diamond, a prerequisite for advanced optical and quantum applications.
- Quantum Center Synthesis: The REM-C system provides growth conditions favorable for the efficient incorporation of Group IV elements (Si, Ge, Sn), leading to the formation of critical quantum emitters: SiV- (737 nm), GeV- (602 nm), and SnV- (620 nm) centers.
- Growth Rates: Average linear diamond growth rates up to 500 ”m/h were achieved (La-C system), demonstrating high efficiency compared to traditional HPHT methods.
- Morphological Complexity: Synthesis using heavy REMs resulted in crystals exhibiting highly complex and unusual faces, including tetragon-trioctahedron ({311}, {411}) and trigon-trioctahedron ({211}, {661}) faces.
- Core Value Proposition: This methodology opens a new pathway for producing specialized diamond materials essential for emerging quantum technologies, particularly those requiring high concentrations of stable Group IV vacancy centers.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results, primarily focusing on optimal conditions (2000 °C) and key material properties.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Synthesis Pressure | 7.8 | GPa | All HPHT experiments |
| Optimal Synthesis Temperature | 2000 | °C | Yielded highest conversion and growth rates |
| Max Linear Growth Rate (La-C) | 500 | ”m/h | Average rate at 2000 °C |
| Max Linear Growth Rate (Heavy REM) | 250 | ”m/h | Tb, Dy, Ho, Er, Tm, Yb, Lu systems |
| Max Graphite-to-Diamond Conversion | 100 | % | Achieved in Sc, La, Yb, Lu systems at 2000 °C |
| Max Nucleation Site Density | 10000 | cm-2 | Observed in Gd-C system |
| Max Crystal Size (Aggregate) | 1.5 | mm | Sc-C system |
| Max Crystal Size (Single Crystal) | 0.7 | mm | Ho-C system |
| SiV- ZPL Wavelength | 737 | nm | Silicon-Vacancy color center |
| GeV- ZPL Wavelength | 602 | nm | Germanium-Vacancy color center |
| SnV- ZPL Wavelength | 620 | nm | Tin-Vacancy color center |
| Boron Impurity Concentration | 0.1-1 | atomic ppm | Estimated in Type IIb samples (heavy REMs) |
| PL Measurement Temperature | 80 | K | Low-temperature spectroscopic analysis |
Key Methodologies
Section titled âKey MethodologiesâThe diamond synthesis was conducted using the HPHT method, utilizing a split-sphere multi-anvil apparatus.
- HPHT Setup: Experiments were performed at a constant pressure of 7.8 GPa, with temperatures ranging from 1800 °C to 2100 °C.
- Starting Materials: Graphite rods (99.97% purity), 15 different Rare Earth Metals (99.99% purity), and synthetic diamond seed crystals (0.5 mm cuboctahedrons) were used.
- Cell Assembly: Graphite capsules (1.5 mm thick walls) were used, enveloped by a 0.1 mm thick Molybdenum (Mo) foil to prevent contamination from the high-pressure cell components.
- Doping Strategy: For Group IV center synthesis, 10 wt% of Ge or Sn was added to the Ce catalyst system.
- Post-Synthesis Processing: Recovered products were treated with hot nitric/hydrochloric acid mixture, followed by K2Cr2O7 and concentrated H2SO4 to dissolve the metal catalyst and residual graphite.
- Morphological Analysis: Scanning Electron Microscopy (SEM) and optical microscopy utilizing Differential Interference Contrast (DIC) and Total Interference Contrast (TIC) methods were employed to study crystal morphology and surface microrelief.
- Spectroscopic Analysis: Fourier Transform Infrared (FTIR) spectroscopy confirmed nitrogen-free Type II characteristics. Photoluminescence (PL) spectroscopy (395 nm excitation, 80 K) was used to identify SiV, GeV, and SnV color centers.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research validates the critical role of high-purity, doped diamond in quantum technology. While the paper utilizes HPHT, 6CCVD specializes in MPCVD, which offers superior control, scalability, and purity for producing the exact materials required to replicate and advance this work.
| Research Requirement/Challenge | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| High-Purity, Nitrogen-Free Diamond | Optical Grade SCD (0.1”m - 500”m thickness) | 6CCVDâs MPCVD process delivers ultra-low nitrogen SCD (Type IIa), providing the ideal host lattice for stable, high-coherence quantum emitters (SiV, GeV, SnV). |
| Controlled Group IV Doping (SiV, GeV, SnV) | Precision Doping via MPCVD | MPCVD allows for highly uniform and controllable incorporation of Group IV elements (Si, Ge, Sn) using gaseous precursors, offering better spatial and concentration control than HPHT melt additives. |
| Scalability and Large Dimensions | PCD Wafers up to 125mm; SCD Plates up to 10mm Substrates | The paperâs crystals are small (up to 1.5 mm). 6CCVD provides large-area SCD and PCD wafers, enabling scalable fabrication of quantum devices and optical components. |
| Surface Quality for Optical Interfacing | Ultra-Low Roughness Polishing | The complex faces observed in the paper require precise finishing. 6CCVD guarantees Ra < 1nm for SCD and Ra < 5nm for inch-size PCD, essential for minimizing scattering losses in waveguides and optical cavities. |
| Electronic/Electrochemical Applications | Heavy Boron-Doped Diamond (BDD) | For applications requiring semiconducting properties (Type IIb, as observed in heavy REM systems), 6CCVD supplies custom BDD materials (SCD or PCD) with tailored conductivity. |
| Device Integration & Custom Geometry | Custom Metalization and Laser Cutting | 6CCVD offers in-house metalization (Au, Pt, Pd, Ti, W, Cu) and laser cutting services to create custom geometries, simplifying the integration of doped diamond into microelectronic and quantum circuits. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in optimizing MPCVD growth recipes for specific defect engineering. We can assist researchers and engineers in transitioning from HPHT synthesis to scalable MPCVD production for similar Group IV Quantum Emitter projects, ensuring precise control over defect density and location.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 1999 - Advances in New Diamond Science and Technology
- 1979 - The Properties of Diamond
- 1992 - The Properties of Natural and Synthetic Diamond
- 2015 - Handbook of Crystal Growth (Chap. 17) [Crossref]