13C and 11B NMR Spectroscopy of High-Pressure High-Temperature Boron-Doped Diamonds
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2025-04-01 |
| Journal | Journal of Experimental and Theoretical Physics Letters |
| Authors | Z. N. Volkova, В. П. Филоненко, R. Kh. Bagramov, И. П. Зибров, Nikolai Mikhilovich Shchelkachev |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Boron-Doped Diamond Spectroscopy
Section titled “Technical Documentation & Analysis: Boron-Doped Diamond Spectroscopy”This document analyzes the findings of the research paper ” ${}^{13}$C and ${}^{11}$B NMR Spectroscopy of High-Pressure High-Temperature Boron-Doped Diamonds” and outlines how 6CCVD’s advanced MPCVD capabilities provide superior material solutions for replicating and extending this research.
Executive Summary
Section titled “Executive Summary”- Material Focus: Analysis of high-concentration Boron-Doped Diamond (BDD) micropowders synthesized via catalyst-free High-Pressure High-Temperature (HPHT) methods.
- Doping Levels: Two samples were studied with estimated boron concentrations of 1% (BDD-1) and 2.5% (BDD-2).
- Structural Disorder: Nuclear Magnetic Resonance (NMR) spectroscopy confirmed significant structural disorder, particularly in the higher-doped BDD-2 sample.
- Defect Identification: ${}^{13}$C NMR revealed a substantial presence of sp2-hybridized carbon bonds, indicating low-dimensional defects retained from the graphite precursor.
- Boron Environment: ${}^{11}$B NMR spectra were decomposed into four components, identifying boron in mixed environments: tetragonal (BC4) and trigonal (BC3) coordination with carbon atoms.
- High-Defect Boron: An additional ${}^{11}$B signal (63-65 ppm chemical shift) was attributed to boron atoms concentrated in highly defective regions, such as dislocation clusters and sub-boundaries.
- 6CCVD Value Proposition: 6CCVD offers MPCVD BDD films and wafers with superior crystalline quality and precise doping control, minimizing the detrimental sp2 content and structural impurities inherent to the HPHT powder method.
Technical Specifications
Section titled “Technical Specifications”The following hard data points were extracted from the research paper, detailing synthesis conditions and material characteristics.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Boron Concentration (BDD-1) | 1 | % | Estimated |
| Boron Concentration (BDD-2) | 2.5 | % | Estimated |
| Synthesis Pressure Range | 7.0-8.0 | GPa | HPHT Conditions |
| Synthesis Temperature (BDD-1) | 1550 ± 30 | °C | HPHT Conditions |
| Synthesis Temperature (BDD-2) | 1750 ± 30 | °C | HPHT Conditions |
| Lattice Parameter (BDD-1) | 3.5721(3) | Å | Increased due to B doping |
| Lattice Parameter (BDD-2) | 3.5786(3) | Å | Highest B concentration |
| Reference Diamond Lattice Parameter | 3.567 | Å | Undoped diamond |
| ${}^{13}$C NMR Chemical Shift (BDD-1 Max) | 58 | ppm | Indicates disorder/sp2 bonds |
| ${}^{11}$B NMR Chemical Shift (BC4/Tetragonal) | 21-28 | ppm | Main component (Line 3) |
| ${}^{11}$B NMR Chemical Shift (Defective Areas) | 63-65 | ppm | Line 4 (Dislocation clusters, sub-boundaries) |
| ${}^{11}$B NMR Line Width (BDD-2, Line 3) | 59 | ppm | Δ${}_{1/2}$ for BC4/BC3 mixture |
Key Methodologies
Section titled “Key Methodologies”The synthesis and characterization of the boron-doped diamond micropowders followed these steps:
- Precursor Preparation: Mixtures of high-temperature pitch, globular nanocarbon, and submicron amorphous boron powder were prepared, targeting a Boron to Carbon (B:C) ratio of 1:15.
- Mixing and Drying: Components were mixed in a ball mill using hard-alloy balls in hexane for 1 hour, then dried at 50 °C.
- HPHT Synthesis: Borated diamond micropowders were synthesized in toroid-type chambers (0.3 and 2.5 cm3 reaction volume).
- Thermobaric Treatment:
- Pressure was increased to 7.0-8.0 GPa.
- Temperature was raised to 1550-1750 °C.
- Isothermal holding times varied (5 s for BDD-2, 100 s for BDD-1).
- Purification: Resulting diamond powders were chemically purified to remove residual impurities.
- Phase Analysis: X-ray Diffraction (XRD) was used to analyze phase composition and calculate lattice parameters, confirming the presence of B${}_{4}$C, cBN, and BDG impurities.
- Microscopy: Electron microscopy (JSM-6390 JEOL) was used to analyze crystal morphology (particle sizes up to 30 µm).
- NMR Spectroscopy: High-resolution ${}^{11}$B and ${}^{13}$C MAS NMR spectra were obtained at 11.74 T to analyze local boron and carbon environments.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The research demonstrates the challenges of achieving high-quality, highly-doped BDD using HPHT methods, specifically the introduction of structural disorder (sp${}^{2}$ bonds) and secondary phases (B${}_{4}$C, cBN). 6CCVD’s advanced MPCVD technology provides the necessary control to overcome these limitations, delivering high-purity BDD materials essential for advanced applications like superconductivity and electrochemistry.
| Category | 6CCVD Solution & Value Proposition |
|---|---|
| Applicable Materials | Heavy Boron-Doped Diamond (BDD) Wafers (MPCVD): 6CCVD specializes in producing high-quality BDD films and substrates via MPCVD. This method offers superior control over boron incorporation compared to HPHT powder synthesis, minimizing the detrimental sp${}^{2}$ carbon content and secondary phase impurities (B${}_{4}$C, cBN) identified in the paper. |
| Material Specifications | Precise Doping and Thickness: We supply BDD materials with precise, uniform doping levels (up to 10${}^{21}$ atoms/cm${}^{3}$) required for metallic and superconducting regimes. Thicknesses are customizable for both SCD and PCD from 0.1 µm up to 500 µm. |
| Structural Quality Control | Ultra-Low Defect Density: The HPHT samples showed significant disorder, with boron accumulating in highly defective areas (63-65 ppm NMR signal). 6CCVD’s MPCVD growth yields high-purity SCD and PCD with industry-leading surface quality (Ra < 1 nm for SCD; Ra < 5 nm for inch-size PCD), ensuring minimal dislocation clusters and sub-boundaries. |
| Customization Potential | Large Area and Custom Dimensions: While the research used micropowders, 6CCVD supports scaling up applications. We offer PCD wafers up to 125 mm in diameter and SCD plates with custom laser cutting and shaping services to meet specific device geometry requirements. |
| Device Integration | Advanced Metalization Services: For researchers integrating BDD into functional devices (e.g., electrochemical electrodes), 6CCVD provides in-house metalization capabilities, including deposition of Au, Pt, Pd, Ti, W, and Cu, ensuring reliable ohmic contacts. |
| Engineering Support | Expert Consultation for Superconducting Diamond: The paper emphasizes the critical role of the local boron environment (BC4 vs. BC3) in determining conductivity. Our in-house PhD material science team assists researchers in selecting optimal BDD growth parameters to maximize the desired BC4 incorporation and minimize structural defects for high-performance superconducting diamond projects. |
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Diamond micropowders with a boron content of 1 and 2.5% that have been synthesized under high pressure and high temperature conditions and studied. The method of nuclear magnetic resonance on 13 C and 11 B nuclei has been used for a comparative analysis of boron-doped diamond and boron-doped graphite. It has been shown that the structure of diamonds with a high boron content is disordered and contains a significant amount of carbon with trigonal coordination. The main signal in the 11 B spectra of diamond microcrystals is due to the sum of contributions from single boron atoms with tetragonal and trigonal carbon environments. An additional signal in the spectra with a chemical shift of more than 60 ppm can be due to boron atoms in the areas of dislocation clusters, sub-boundaries, and other defective areas.