Decay rate enhancement of diamond NV-centers on diamond thin films
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-06-24 |
| Journal | Optics Express |
| Authors | Hao Li, JunâYu Ou, V.A. Fedotov, Nikitas Papasimakis |
| Institutions | University of Southampton |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Decay Rate Enhancement of NV-Centers
Section titled âTechnical Documentation & Analysis: Decay Rate Enhancement of NV-CentersâThis document analyzes the requirements and findings of the research paper âDecay rate enhancement of diamond NV-centers on diamond thin filmsâ and maps them directly to the advanced MPCVD diamond capabilities offered by 6CCVD.
Executive Summary
Section titled âExecutive SummaryâThis study successfully demonstrates precise control over the emission statistics of Nitrogen-Vacancy (NV) quantum emitters by leveraging thin-film diamond structures, a critical step for integrated quantum photonics and sensing.
- Core Achievement: Experimental demonstration of a two-fold enhancement in the decay rate of NV$^0$ centers, reducing the average lifetime from 30 ns (on bare Si) to 17 ns (on a diamond thin film).
- Mechanism: The enhancement is attributed to the coupling of NV emitters to optical slab modes (Fabry-Perot modes) supported by the thin diamond film, leading to a significant Purcell effect.
- Tunability: The radiative decay rate was shown to be highly tunable, varying by up to 90% based on the precise thickness of the diamond film (e.g., 90 nm vs. 160 nm).
- Material Requirement: The experiment relies on high-quality, precisely controlled thin diamond films (200 nm thickness) deposited on silicon substrates.
- 6CCVD Value Proposition: 6CCVD specializes in producing MPCVD diamond films with the requisite sub-micron thickness control (0.1 ”m to 500 ”m) and large-area uniformity (up to 125 mm) necessary to replicate and scale this quantum control mechanism.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper, highlighting the critical material and experimental parameters.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Film Thickness (Exp.) | 200 | nm | Thickness of diamond film on Si substrate |
| Substrate Thickness | 500 | ”m | Thickness of underlying Silicon wafer |
| NV$^0$ Emission Wavelength (ZPL) | 575 | nm | Zero Phonon Line (ZPL) used for detection |
| Spectrometer Wavelength Range | 3.6 | nm | Range selected around 575 nm ZPL |
| Average NV$^0$ Lifetime (Bare Si, Exp) | 30 ± 6 | ns | Mean lifetime (”) and standard deviation (Ï) |
| Average NV$^0$ Lifetime (Diamond Film, Exp) | 17 ± 4 | ns | Mean lifetime (”) and standard deviation (Ï) |
| Decay Rate Enhancement Factor | 2.0 | N/A | Two-fold enhancement (30 ns / 17 ns) |
| Radiative Decay Rate Tuning Depth | Up to 89 | % | Achieved by varying film thickness (90 nm vs 160 nm) |
| Electron Beam Current (TR-CL) | ~1.8 | nA | Maintained during time-resolved measurement |
| Diamond Refractive Index (ndiamond) | 2.40 | N/A | Used for 3D electromagnetic modeling (575 nm) |
| Silicon Refractive Index (nSi) | 4.00 + 0.03i | N/A | Used for 3D electromagnetic modeling (575 nm) |
Key Methodologies
Section titled âKey MethodologiesâThe experimental procedure focused on characterizing the NV$^0$ lifetime dependence on the local dielectric environment provided by the thin diamond film.
- Nanodiamond Preparation: Nanodiamonds (~120 nm diameter, containing ~103 NV centers) were dispersed in methanol using a 10-minute ultrasonic bath.
- Substrate Fabrication: Two substrates were prepared: a bare 500 ”m thick Si wafer and a 200 nm thick diamond film grown on a 500 ”m thick Si wafer.
- Deposition: Nanodiamond clusters (120 nm to 1500 nm size range) were deposited onto both substrates via drop casting.
- Characterization Setup: Time-Resolved Cathodoluminescence (TR-CL) was performed using a Scanning Electron Microscope (SEM) operating in fixed-spot mode (10 kV LaB6 source).
- Measurement Technique: A pulsed electron beam, generated by a beam blanker and wave function generator, was synchronized with a single photon counting controller (TCSPC) to measure photon counting histograms.
- Data Selection: Measurements focused exclusively on the neutral NV$^0$ center emission at the Zero Phonon Line (ZPL) of 575 nm.
- Modeling: Full-wave 3D electromagnetic modeling (COMSOL 5.3a) was used to simulate dipole emission from a 60 nm nanodiamond sphere, allowing separation of radiative (ÎłRad) and non-radiative (ÎłNon) decay rates.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful control of NV decay rates hinges entirely on the quality and precise dimensional control of the supporting diamond thin film. 6CCVD is uniquely positioned to supply the high-specification MPCVD diamond materials required for scaling this quantum technology.
Applicable Materials for Quantum Emitter Control
Section titled âApplicable Materials for Quantum Emitter ControlâTo replicate and advance the research on Purcell enhancement and decay rate tuning, 6CCVD recommends the following materials, optimized for optical and quantum applications:
| 6CCVD Material | Specification | Application Relevance |
|---|---|---|
| Optical Grade SCD Thin Films | SCD (0.1 ”m to 500 ”m thickness), Ra < 1 nm polishing. | Ideal for integrated photonics requiring minimal scattering loss and high crystal quality for superior optical mode confinement. |
| High-Quality PCD Wafers | PCD (0.1 ”m to 500 ”m thickness), up to 125 mm diameter. | Cost-effective solution for large-area quantum sensing arrays or when the NV centers are introduced via deposited nanodiamonds. |
| Custom Substrates | Diamond films grown directly on Si or other semiconductor substrates. | Directly addresses the substrate requirement (Diamond film on Si) used in this study, ensuring robust device integration. |
Customization Potential for Advanced Research
Section titled âCustomization Potential for Advanced ResearchâThe research demonstrates that the decay rate is critically dependent on the film thickness, requiring extreme precision in material manufacturing. 6CCVDâs custom capabilities directly address this need:
- Precision Thickness Tuning: The paper showed optimal tuning at specific thicknesses (e.g., 90 nm, 160 nm). 6CCVD offers MPCVD diamond films with thickness control from 0.1 ”m (100 nm) up to 500 ”m, enabling researchers to precisely target specific Fabry-Perot mode resonances for maximum Purcell enhancement.
- Large-Area Scaling: We provide diamond plates and wafers up to 125 mm in diameter (PCD), essential for scaling laboratory experiments into commercial quantum devices and wafer-level processing.
- Surface Engineering: For future integrated devices where nanodiamonds are replaced by implanted or grown NV centers, 6CCVD offers ultra-smooth polishing (Ra < 1 nm for SCD) to minimize surface scattering and maximize coupling efficiency to guided modes.
- Metalization Services: While not used in this specific paper, 6CCVD offers in-house metalization (Au, Pt, Pd, Ti, W, Cu) for creating integrated photonic structures, electrodes, or contact pads necessary for advanced quantum device architectures.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house team of PhD material scientists and engineers can assist researchers in selecting the optimal diamond material (SCD vs. PCD, specific thickness, and surface finish) required for similar quantum emitter control and integrated photonics projects. We provide global shipping (DDU default, DDP available) to ensure rapid delivery of custom materials worldwide.
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We demonstrate experimentally two-fold enhancement of the decay rate of NV° centers on diamond/Si substrate as opposed to a bare Si substrate. We link the decay enhancement to the interplay between the excitation of substrate modes and the presence of non-radiative decay channels. We show that the radiative decay rate can vary by up to 90% depending on the thickness of the diamond film.