Lightly Boron-Doped Nanodiamonds for Quantum Sensing Applications
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-02-10 |
| Journal | Nanomaterials |
| Authors | Masfer Alkahtani, Д. К. Жарков, A. V. Leontyev, A. G. Shmelev, В. Г. Никифоров |
| Institutions | Texas A&M University, King Abdulaziz City for Science and Technology |
| Citations | 8 |
| Analysis | Full AI Review Included |
Lightly Boron-Doped Nanodiamonds for Quantum Sensing Applications
Section titled “Lightly Boron-Doped Nanodiamonds for Quantum Sensing Applications”(Analysis of Nanomaterials 2022, 12, 601 by 6CCVD Engineering Team)
Executive Summary
Section titled “Executive Summary”This research validates the potential of co-doped diamond material systems for advanced bio-sensing and quantum applications. 6CCVD specializes in providing the high-purity, engineered diamond substrates necessary to replicate and extend this work.
- Dual-Functionality Demonstrated: Lightly Boron-Doped Nanodiamonds (BNDs) successfully function as both NIR-activated heating agents (808 nm) for hyperthermia and as internal quantum temperature sensors via the Nitrogen-Vacancy (NV) center.
- High Thermal Sensitivity: The BNDs achieved a thermal sensitivity of 250 mK/v/Hz over the critical biological temperature range (298 K to 330 K).
- NV- Stabilization: The negatively charged NV- state, essential for spin-dependent quantum sensing, was stabilized in the boron-rich environment through targeted Nitrogen ion implantation (50 keV, 2 x 1012 ion/cm2) and subsequent 750 °C vacuum annealing.
- Optimized Spin Properties: The co-doped material maintained robust spin properties, reporting a longitudinal relaxation time (T1) of 370 µs and a spin coherence time (T2) of 5 µs.
- Material Relevance: The findings confirm that controlled co-doping (Boron acceptors + Nitrogen donors) in diamond is a viable strategy for creating multifunctional quantum probes.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Boron Doping Level | ~0.5 | wt% | Nanodiamond starting material |
| Nanodiamond Size | 50-70 | nm | Average particle size |
| Nitrogen Implantation Energy | 50 | keV | To create NV centers |
| Nitrogen Implantation Dose | 2 x 1012 | ion/cm2 | To stabilize NV- charge state |
| Annealing Temperature | 750 | °C | Vacuum annealing time: 30 min |
| Heating Laser Wavelength | 808 | nm | Used for hyperthermia/thermoablation |
| Heating Laser Intensity | 50 | W·cm-2 | Used for temperature rise verification |
| Observed Temperature Rise (BNDs) | 15 | °C | Over 20 min irradiation |
| Thermal Sensitivity ($\eta$) | 250 | mK/v/Hz | Calculated using ODMR data |
| Temperature Slope (dM/dT) | -72 | kHz/K | Linear dependence of frequency shift |
| ODMR Linewidth ($\Gamma$) | 17 | MHz | Inhomogeneous width |
| Spin Relaxation Time (T1) | 370 | µs | Longitudinal relaxation |
| Spin Coherence Time (T2) | 5 | µs | Measured using Hahn-echo sequence |
Key Methodologies
Section titled “Key Methodologies”The successful creation of stable NV- centers in the Boron-doped matrix relied on precise chemical cleaning and controlled post-growth processing, which are core capabilities offered by 6CCVD for bulk diamond substrates.
- Acid Cleaning: BNDs were cleaned in a boiling mixture of nitric and sulfuric acids (HNO3:H2SO4 = 1:1) at 120 °C to selectively etch graphitic carbon (sp2).
- Surface Oxidation: Samples were air oxidized at 550 °C for 10 minutes to remove residual sp2 carbon, preventing quenching of NV luminescence.
- Nitrogen Implantation: Nitrogen ions were implanted at 50 keV with a dose of 2 x 1012 ion/cm2 to introduce donor defects necessary for NV center formation and NV- charge state stabilization.
- NV Center Formation: Samples were annealed in a vacuum at 750 °C for 30 minutes to mobilize vacancies toward the implanted nitrogen atoms.
- Optical Characterization: A custom confocal laser scanning microscope equipped with 532 nm (green) and 808 nm (NIR) lasers was used for fluorescence and Optically Detected Magnetic Resonance (ODMR) measurements.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD provides the high-quality, engineered MPCVD diamond substrates and post-processing services required to advance research in quantum thermometry and bio-sensing, offering superior material control compared to nanodiamond powders.
Applicable Materials
Section titled “Applicable Materials”To replicate or extend this research into bulk diamond devices or high-performance quantum sensors, 6CCVD recommends the following engineered materials:
- Heavy Boron Doped Polycrystalline Diamond (BDD-PCD): For applications requiring high NIR absorption and electrical conductivity, similar to the heating function demonstrated. 6CCVD offers BDD films up to 500 µm thick, suitable for large-area thermal management or electrochemical sensing integration.
- Optical Grade Single Crystal Diamond (SCD): For maximizing the quantum sensing performance (T1 and T2). Our high-purity SCD minimizes native defects and strain, providing an optimal host lattice for implanted NV centers, potentially yielding T2 times significantly longer than the 5 µs reported here.
- Custom Co-Doped MPCVD Diamond: 6CCVD can grow diamond films with precise, controlled in-situ incorporation of both Boron and Nitrogen, eliminating the need for post-growth implantation in some cases, or providing a highly uniform starting material for subsequent processing.
Customization Potential
Section titled “Customization Potential”The methodology relies heavily on precise defect engineering (implantation and annealing). 6CCVD offers comprehensive in-house services to meet these exact specifications:
| Research Requirement | 6CCVD Customization Service | Specification Range |
|---|---|---|
| Defect Creation (N Implantation) | Custom Ion Implantation Services | Precise implantation of N, Si, or other species at specified energies (keV to MeV range) and doses (up to 1015 ion/cm2). |
| NV Center Activation | Controlled High-Vacuum Annealing | High-temperature annealing (up to 1500 °C) in high vacuum or inert gas environments to optimize vacancy mobility and NV- yield. |
| Device Integration | Custom Metalization | In-house deposition of thin films (Au, Pt, Pd, Ti, W, Cu) for creating microwave striplines or electrical contacts necessary for ODMR and magnetic sensing experiments. |
| Substrate Size & Finish | Large-Area Polishing & Custom Dimensions | Plates/wafers up to 125mm (PCD) or high-quality SCD up to 10mm thickness. Polishing capability to achieve surface roughness Ra < 1nm (SCD) or Ra < 5nm (Inch-size PCD). |
Engineering Support
Section titled “Engineering Support”The successful implementation of BNDs for dual-function bio-probes requires expert knowledge in defect physics and material science. 6CCVD’s in-house PhD team can assist researchers and engineers with material selection, defect optimization, and process development for similar Quantum Sensing and Hyperthermia projects. We ensure the chosen diamond substrate meets the stringent requirements for both optical transparency (808 nm window) and quantum coherence.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Unlike standard nanodiamonds (NDs), boron-doped nanodiamonds (BNDs) have shown great potential in heating a local environment, such as tumor cells, when excited with NIR lasers (808 nm). This advantage makes BNDs of special interest for hyperthermia and thermoablation therapy. In this study, we demonstrate that the negatively charged color center (NV) in lightly boron-doped nanodiamonds (BNDs) can optically sense small temperature changes when heated with an 800 nm laser even though the correct charge state of the NV is not expected to be as stable in a boron-doped diamond. The reported BNDs can sense temperature changes over the biological temperature range with a sensitivity reaching 250 mK/√Hz. These results suggest that BNDs are promising dual-function bio-probes in hyperthermia or thermoablation therapy as well as other quantum sensing applications, including magnetic sensing.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
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