Diamonds from the Mir Pipe (Yakutia) - Spectroscopic Features and Annealing Studies

At a Glance

Metadata	Details
Publication Date	2021-03-31
Journal	Crystals
Authors	Mariana I. Rakhmanova, Andrey Komarovskikh, Yuri N. Palyanov, Alexander A. Kalinin, O. P. Yuryeva
Institutions	Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences
Citations	11
Analysis	Full AI Review Included

Technical Documentation & Analysis: Defect Engineering and Annealing in Diamond

This document analyzes the research paper “Diamonds from the Mir Pipe (Yakutia): Spectroscopic Features and Annealing Studies” to highlight the critical role of defect control, high-temperature processing, and material purity—core competencies of 6CCVD.

Executive Summary

This study provides crucial insights into the stability and transformation of intrinsic and impurity-related defects in diamond under extreme thermal and pressure conditions, directly informing advanced material engineering for applications such as quantum sensing and high-power optics.

Defect Transformation Focus: The research utilized PL, IR, and EPR spectroscopy to track the annihilation and formation of nitrogen (N3, H3, H4), nickel-boron (Ni-B, 418 nm), and vacancy-related centers (NV^-, NV⁰) in Type IIa, IaAB, and IaB diamonds.
Extreme Processing Validation: Step-by-step annealing (600 °C to 1700 °C) included High-Pressure/High-Temperature (HPHT) treatment at 6 GPa and 1500 °C/1700 °C, demonstrating the necessity of high-pressure stabilization for defect migration studies.
Vacancy Mobility Confirmed: The complete annealing of the 563.5 nm defect at 600 °C confirmed interstitial carbon vacancy annihilation, while the disappearance of the GR1 center reflected vacancy mobility.
Dislocation/Strain Correlation: The 490.7 nm system, correlated with dangling bonds in dislocation cores, annealed out completely at 1700 °C, reflecting thermally activated diffusion of dislocations.
Superdeep Diamond Signatures: Annealing at 1500 °C resulted in the appearance of the 558.5 nm and 576 nm centers, characteristic of superdeep diamonds, indicating high effective storage temperatures.
Material Purity Requirement: The study relied on distinguishing between ultra-low nitrogen (Type IIa) and high-nitrogen (Type IaB) samples, emphasizing the need for precise impurity control in synthetic diamond growth.

Technical Specifications

The following hard data points were extracted from the research paper, focusing on processing parameters and defect characteristics.

Parameter	Value	Unit	Context
HPHT Annealing Pressure	6.0	GPa	Stabilizing pressure for 1500 °C and 1700 °C treatments
HPHT Annealing Duration	1.5	hours	Treatment time at 6 GPa
Low-T Annealing Duration	2	hours	Treatment time at 600 °C and 1000 °C (ambient pressure)
Total Nitrogen Content (N_total)	Up to 1900	ppm	Measured via IR spectroscopy
Ni-B Defect PL Center	417.4 + 418.7	nm	Characteristic of Type IIa diamonds
563.5 nm Defect Annihilation	600	°C	Interstitial carbon vacancy annihilation
676.5 nm Defect Annihilation	1500	°C	Thermally activated mobility (dislocation/nitrogen)
613 nm Defect Annihilation	1700	°C	Thermally activated mobility (dislocation/nitrogen)
490.7 nm Defect Annihilation	1700	°C	Complete annealing (thermally activated dislocation diffusion)
Platelet Peak Absorption	Up to 7.2	cm^-1	Measured at 1360-1370 cm^-1
EPR g-factor (490.7 system)	2.0032	-	Correlated with dangling bonds

Key Methodologies

The experimental procedure involved rigorous material characterization followed by controlled, step-by-step thermal and pressure treatments.

Sample Selection and Preparation: 21 colorless octahedral natural diamonds (5.4-55.0 mg) were categorized into Type IIa, IaAB, and IaB based on IR spectra. Four samples were selected for annealing, requiring the polishing of two opposite octahedral faces (0.5 mg weight loss).
Initial Spectroscopic Characterization: Samples were analyzed using Infrared (IR) spectroscopy (700-4000 cm^-1), Photoluminescence (PL) spectroscopy (80 K, 313 nm, 405 nm, 532 nm excitation), and Electron Paramagnetic Resonance (EPR) spectroscopy (80 K and 300 K).
Ambient Pressure Annealing: Samples were annealed in a graphite crucible at 600 °C and 1000 °C for 2 hours to study low-temperature defect mobility (e.g., 563.5 nm center annihilation and H3/H4 center formation).
HPHT Annealing: High-temperature treatments at 1500 °C and 1700 °C were performed under a stabilizing pressure of 6.0 GPa for 1.5 hours using a split-sphere multi-anvil apparatus (BARS) to simulate mantle conditions and induce high-energy defect migration.
Post-Treatment Analysis: PL and EPR spectra were measured after each annealing step to quantify the transformation of specific defects, including the formation of NV centers (NV^-, NV⁰) and the annihilation of strain-related centers (490.7 nm, 613 nm, 676.5 nm).

6CCVD Solutions & Capabilities

This research underscores the critical need for precise control over impurities, vacancies, and post-growth processing—areas where 6CCVD’s MPCVD capabilities provide a significant advantage over natural or traditional HPHT synthesis.

Applicable Materials

To replicate or extend the defect engineering demonstrated in this paper, researchers require materials with highly controlled impurity profiles and crystalline quality.

Research Requirement	6CCVD Material Solution	Technical Advantage
Type IIa Replication (Ni-B studies)	Optical Grade Single Crystal Diamond (SCD)	Ultra-low nitrogen content (< 1 ppm) necessary to isolate Ni-B defects (418 nm) and ensure high optical transparency.
Controlled N/V Defect Creation (NV Centers)	Nitrogen-Doped SCD	Precise control of substitutional nitrogen concentration (P1 centers) and subsequent vacancy introduction (via irradiation or HPHT simulation) to maximize NV^- yield and coherence.
Boron-Doped Studies (Ni-B, Semiconducting)	Boron-Doped Diamond (BDD)	Available in both SCD and PCD formats, allowing for controlled p-type conductivity and investigation of complex Ni-B interactions.
High-Power/Thermal Management	Thermal Grade PCD	Plates/wafers up to 125mm in diameter for large-scale thermal applications requiring high purity and mechanical stability.

Customization Potential

The study utilized polished samples and required specific defect creation/stabilization steps. 6CCVD offers comprehensive customization services to meet these advanced engineering needs.

Precision Polishing: The paper required polishing of octahedral faces. 6CCVD guarantees surface roughness of Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD, essential for high-resolution spectroscopic analysis and minimizing surface defects.
Custom Dimensions and Geometry: We provide custom plates and wafers up to 125mm (PCD) and SCD substrates up to 10mm thick, allowing for larger experimental platforms than the small natural crystals (5.4-55.0 mg) used in the study.
Advanced Metalization: While the paper focused on intrinsic defects, related studies often require surface contacts. 6CCVD offers in-house metalization capabilities, including Ti, Pt, Au, Pd, W, and Cu, crucial for creating ohmic contacts or integrated quantum devices.
Laser Cutting and Shaping: Custom laser cutting services ensure precise sample geometry for integration into complex experimental setups, such as multi-anvil HPHT apparatus (BARS).

Engineering Support

The complex defect transformations observed during HPHT annealing (e.g., nitrogen diffusion, vacancy migration, dislocation annihilation) require expert material consultation.

6CCVD’s in-house PhD team specializes in MPCVD defect engineering and can assist researchers in designing material recipes to:

Optimize NV Center Yield: Tailoring nitrogen concentration and post-growth annealing protocols to maximize the density and stability of NV^- centers for quantum sensing projects.
Simulate HPHT Stability: Providing materials with known defect profiles suitable for high-temperature and high-pressure stability testing, replicating the conditions studied in this paper.
Control Strain and Dislocations: Delivering low-strain SCD material, minimizing the background signal from deformation-related centers like the 490.7 nm system observed in the study.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

For this study, 21 samples of colorless octahedral diamonds (weighing 5.4-55.0 mg) from the Mir pipe (Yakutia) were investigated with photoluminescence (PL), infrared (IR), and electron paramagnetic resonance (EPR) spectroscopies. Based on the IR data, three groups of diamonds belonging to types IIa, IaAB, and IaB were selected and their spectroscopic features were analyzed in detail. The three categories of stones exhibited different characteristic PL systems. The type IaB diamonds demonstrated dominating nitrogen-nickel complexes S2, S3, and 523 nm, while they were less intensive or even absent in the type IaAB crystals. The type IIa diamonds showed a double peak at 417.4 + 418.7 nm (the 418 center in this study), which is assumed to be a nickel-boron defect. In the crystals analyzed, no matter which type, 490.7, 563.5, 613, and 676.3 nm systems of various intensity could be detected; moreover, N3, H3, and H4 centers were very common. The step-by-step annealing experiments were performed in the temperature range of 600-1700 °C. The treatment at 600 °C resulted in the 563.5 nm system’s disappearance; the interstitial carbon vacancy annihilation could be considered as a reason. The 676.5 nm and 613 nm defects annealed out at 1500 °C and 1700 °C, respectively. Furthermore, as a result of annealing at 1500 °C, the 558.5 and 576 nm centers characteristic of superdeep diamonds from São Luis (Brazil) appeared. These transformations could be explained by nitrogen diffusion or interaction with the dislocations and/or vacancies produced.

Tech Support

Original Source

DOI: https://doi.org/10.3390/cryst11040366

References

2015 - Specific features of diamonds from promising areas of Sibirian platform [Crossref]
1966 - The origin of types I, II diamonds and reasons for their different physical properties
2017 - Nature of Type IaB Diamonds from the Mir Kimberlite Pipe (Yakutia): Evidence from Spectroscopic Observation [Crossref]
2015 - The Characteristic Photoluminescence and EPR Features of Superdeep Diamonds (São-Luis, Brazil) [Crossref]
1982 - The Kinetics of the Aggregation of Nitrogen Atoms in Diamond [Crossref]
2015 - Multiple Growth Events in Diamonds with Cloudy Microinclusions from the Mir Kimberlite Pipe: Evidence from the Systematics of Optically Active Defects [Crossref]
2006 - Directional Chemical Variations in Diamonds Showing Octahedral Following Cuboid Growth [Crossref]