Formation mechanism and regulation of silicon vacancy centers in polycrystalline diamond films
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-11-28 |
| Journal | Acta Physica Sinica |
| Authors | Junpeng Li, Zeyang Ren, Jinfeng Zhang, Han-Xue Wang, Yuan-Chen Ma |
| Institutions | Xidian University, Wuhu Institute of Technology |
| Citations | 2 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: SiV Center Regulation in Polycrystalline Diamond Films
Section titled âTechnical Documentation & Analysis: SiV Center Regulation in Polycrystalline Diamond FilmsâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates precise control over Silicon Vacancy (SiV) color center photoluminescence (PL) intensity in Polycrystalline Diamond (PCD) films grown on silicon substrates using Microwave Plasma Chemical Vapor Deposition (MPCVD).
- Core Achievement: Effective regulation of SiV PL intensity by tuning the ratio of Nitrogen (N2) and Oxygen (O2) in the growth atmosphere.
- Performance Range: Achieved an unprecedented SiV PL peak to Diamond intrinsic peak ratio ranging from a minimum of 1.48 to a maximum of 334.46.
- Mechanism Confirmation: N2 acts as a promoter, increasing diamond growth rate, inducing preferred crystal orientation, and accelerating the diffusion of Si from the substrate into the diamond lattice to form SiV centers.
- Inhibition Effect: O2 acts as an inhibitor, reducing the growth rate, refining grain size, and trapping Si as Si-monomer on the grain surface, thereby suppressing SiV formation.
- Material Correlation: High SiV PL intensity is strongly correlated with larger diamond grain size and pronounced preferred crystal orientation.
- Application Relevance: These highly controllable, high-intensity SiV centers are critical for advancing quantum information processing, single-photon sources, and biological marker applications operating in the near-infrared (738 nm).
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results detailing the growth conditions and resulting SiV performance.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| SiV Zero Phonon Line (ZPL) | 738 | nm | Primary emission wavelength |
| Growth Temperature | 950 | °C | Constant for all samples (S1-S5) |
| Microwave Power | 4200 | W | MPCVD system input |
| Chamber Pressure | 185 | mbar | Approximately 1.85 x 104 Pa |
| Max SiV PL Ratio (ISiV/IDiamond) | 334.46 | Unitless | Achieved in Sample S2 (0.01% N2) |
| Min SiV PL Ratio (ISiV/IDiamond) | 1.48 | Unitless | Achieved in Sample S3 (0.25% O2) |
| Max Growth Rate | 3.95 | ”m/h | Sample S2 (N2 optimized) |
| Min Growth Rate | 0.62 | ”m/h | Sample S3 (O2 heavy) |
| Substrate Size | 15 x 15 | mm | (111) intrinsic silicon substrate |
| Diamond Film Thickness Range | ~1.24 to ~7.9 | ”m | Estimated based on 2-hour growth time |
Key Methodologies
Section titled âKey MethodologiesâThe PCD films were synthesized using a custom-built MPCVD system. Precise control over gas composition was the primary variable for defect engineering.
- Substrate Preparation: (111) intrinsic silicon substrates (15 mm x 15 mm) were cleaned via ultrasonic baths (acetone, ethanol, DI water).
- Seeding: Substrates were seeded using a nanodiamond slurry (7-8 nm particles) via ultrasonic treatment (15 min).
- MPCVD Growth Parameters (Fixed):
- Microwave Power: 4200 W
- Pressure: 185 mbar
- Substrate Temperature: 950 °C
- Total Growth Time: 2 hours
- Total Gas Flow: 200 sccm (H2 balance)
- Carbon Source: 10 sccm CH4 (5% concentration)
- Defect Engineering Variables (N2/O2):
- Samples S1 (Reference): 0 N2, 0 O2
- Sample S2 (N2 Optimized): 0.02 sccm N2, 0 O2
- Sample S3 (O2 Inhibited): 0 N2, 0.5 sccm O2
- Sample S4 (N2/O2 Mix 1): 0.02 sccm N2, 0.5 sccm O2
- Sample S5 (N2/O2 Mix 2): 0.02 sccm N2, 1.0 sccm O2
- Characterization: Photoluminescence (PL), Scanning Electron Microscopy (SEM), Raman Spectroscopy, and advanced PL/Raman surface and depth mapping (using 532 nm laser excitation).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical role of precise MPCVD control and high-quality PCD material in achieving high-performance SiV quantum emitters. 6CCVD is uniquely positioned to support the replication and scaling of this work for industrial and advanced research applications.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research, 6CCVD recommends the following materials, tailored for quantum defect engineering:
| 6CCVD Material Solution | Description & Application | Customization Relevance |
|---|---|---|
| Optical Grade PCD Wafers | High-purity Polycrystalline Diamond (PCD) films, ideal for large-area SiV arrays and quantum sensing. Our PCD offers superior thermal management and mechanical stability compared to silicon. | We can provide PCD films up to 125 mm diameter, significantly larger than the 15 mm x 15 mm samples used in this study. |
| Custom Defect-Engineered PCD | PCD films grown specifically on Si substrates (or other custom substrates) with precise gas flow control (N2, O2, SiH4, etc.) to achieve targeted SiV or NV center densities. | We guarantee thickness control from 0.1 ”m up to 500 ”m, allowing researchers to optimize film thickness for specific Si diffusion profiles. |
| High-Purity SCD Substrates | For applications requiring ultimate coherence time and minimal scattering, we offer Single Crystal Diamond (SCD) substrates. SiV centers can be introduced via ion implantation or in-situ growth on SCD. | SCD is available up to 500 ”m thick, with polishing to Ra < 1 nm, essential for high-fidelity optical coupling. |
Customization Potential
Section titled âCustomization PotentialâThe ability to precisely control the SiV center location and density is paramount for quantum applications. 6CCVD offers comprehensive customization services that directly address the needs demonstrated in this paper:
- Advanced Defect Engineering: 6CCVD utilizes state-of-the-art MPCVD reactors capable of sub-sccm gas flow precision, enabling the exact replication of the N2/O2 ratios (e.g., 0.02 sccm N2) required to maximize SiV PL intensity.
- Large-Area Scaling: While the paper used small samples, 6CCVD can scale PCD growth to inch-size wafers (up to 125 mm), providing the necessary platform for commercial device fabrication and large-scale quantum chip integration.
- Surface Finishing: The study noted that SiV centers concentrate on the preferred orientation surfaces of the diamond grains. 6CCVD offers ultra-smooth polishing (Ra < 5 nm for inch-size PCD) to minimize surface scattering losses, crucial for maximizing the collection efficiency of the 738 nm SiV emission.
- Metalization Services: For integrating diamond quantum emitters into photonic or electronic circuits, 6CCVD provides in-house metalization capabilities, including Au, Pt, Pd, Ti, W, and Cu deposition.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in diamond growth kinetics and defect physics. We can assist researchers and engineers with:
- Material Selection: Consulting on whether PCD (for large area/cost efficiency) or SCD (for high coherence) is optimal for specific SiV-based quantum sensing or single-photon source projects.
- Process Optimization: Tailoring MPCVD recipes to achieve specific grain sizes and preferred orientations, directly influencing SiV concentration and PL intensity, as demonstrated in this research.
- Global Logistics: We provide reliable global shipping (DDU default, DDP available) to ensure rapid delivery of custom diamond materials worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Diamond silicon vacancy centers (SiV centers) have important application prospects in quantum information technology and biomarkers. In this work, the formation mechanism and regulation method of SiV center during the growth of polycrystalline diamond on silicon substrate are studied. By changing the ratio of nitrogen content to oxygen content in the growing atmosphere of diamond, the photoluminescence intensity of SiV center can be controlled effectively, and polycrystalline diamond samples with the ratios of SiV center photoluminescence peak to diamond intrinsic peak as high as 334.46 and as low as 1.48 are prepared. It is found that nitrogen promotes the formation of SiV center in the growth process, and the inhibition of oxygen. The surface morphology and photoluminescence spectrum for each of these samples show that the photoluminescence peak intensity of SiV center is positively correlated with the grain size of diamond, and the SiV centerâs photoluminescence peak in the diamond film with obvious preferred orientation of crystal plane is higher. The distribution of Si centers and SiV centers on the surface of polycrystalline diamond are further characterized and analyzed by photoluminescence, Raman surface scanning and depth scanning spectroscopy. It is found that during the growth of polycrystalline diamond, the substrate silicon diffuses first into the diamond grain and then into the crystal structure to form the SiV center. This paper provides a theoretical basis for the development and application of SiV centers in diamond.