Electrical Tuning of Tin-Vacancy Centers in Diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-06-03 |
| Journal | Physical Review Applied |
| Authors | Shahriar Aghaeimeibodi, Daniel Riedel, Alison E. Rugar, Constantin Dory, Jelena VuÄkoviÄ |
| Institutions | Stanford University |
| Citations | 31 |
| Analysis | Full AI Review Included |
Electrical Tuning of SnV Centers in Diamond: 6CCVD Technical Analysis
Section titled âElectrical Tuning of SnV Centers in Diamond: 6CCVD Technical AnalysisâThis document analyzes the research demonstrating the electrical tuning of tin-vacancy (SnV) centers in single-crystal diamond (SCD) via the Stark effect. The findings are highly relevant for quantum network development, requiring ultra-high purity diamond substrates and advanced fabrication capabilities, which are core competencies of 6CCVD.
Executive Summary
Section titled âExecutive Summaryâ- Core Achievement: Demonstrated reversible electrical tuning of SnV center optical transitions in SCD using the direct-current Stark effect.
- Performance Metric: Achieved a tuning range exceeding 1.7 GHz, which is approximately 57 times the natural linewidth (~30 MHz).
- Application Relevance: The tuning range is sufficient to overcome modest inhomogeneous detunings between distinct SnV emitters, enabling the realization of multiple identical quantum nodes.
- Material Requirements: The experiment utilized electronic-grade, low-strain single-crystal diamond (SCD) to minimize native inhomogeneous broadening.
- Defect Engineering: SnV centers were generated via 120Sn+ ion implantation (370 keV) followed by high-temperature vacuum annealing (up to 1100 °C).
- Fabrication Complexity: Required precision nanostructuring (500-nm tall nanopillars/mesas) and custom metalization (5 nm Ti / 30 nm Au) for high-field electrode application.
- Key Finding: Measured Stark coefficients ($\Delta\mu$ and $\Delta\alpha$) are several orders of magnitude smaller than non-inversion-symmetric color centers (e.g., NV-), confirming the SnV centerâs high frequency stability.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper, focusing on material properties and experimental results.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Max Tuning Range | > 1.7 | GHz | Achieved via DC Stark effect |
| Tuning Factor | ~ 57 | Times | Relative to 30 MHz natural linewidth |
| SnV Linewidth (E1, zero field) | 194 ± 12 | MHz | Full Width at Half-Maximum (FWHM) |
| SnV Center Wavelength ($\lambda_{C}$) | 619.254 | nm | C transition, zero field |
| Ground State Splitting (GSS) | 819.6 to 989.4 | GHz | Range observed across different SnV centers (E1-E4) |
| Implantation Ion | 120Sn+ | N/A | Used for SnV center generation |
| Implantation Energy | 370 | keV | Determines implantation depth |
| Expected SnV Depth | ~ 90 | nm | Based on SRIM simulations |
| High Annealing Temperature | 1100 | °C | Vacuum anneal (90 minutes) |
| Quadratic Stark Coefficient ($\Delta\alpha / 4\pi\epsilon_{0}$) | 3.28 ± 0.18 | à 3 | E1 emitter (Predominantly quadratic shift) |
| Linear Stark Coefficient ($\Delta\mu$) | 3.9 ± 0.4 x 10-3 | D | E2 emitter (Predominantly linear shift) |
| Electrode Gap | 1 | ”m | Distance between 4 ”m wide electrodes |
| Max Local Electric Field | ~ 50 | MV/m | Applied across the electrodes |
Key Methodologies
Section titled âKey MethodologiesâThe experiment required precise control over material preparation, defect generation, and nanophotonic fabrication.
- Substrate Preparation: Electronic-grade, single-crystal diamond (SCD) was cleaned using a boiling tri-acid solution (1:1:1 sulfuric/nitric/perchloric acids).
- Surface Etch: The top 300 nm of diamond was removed using an oxygen (O2) plasma etch to prepare the surface.
- SnV Generation: 120Sn+ ion implantation was performed at 370 keV with a dose of 2 x 1011 cm-2, targeting a depth of approximately 90 nm.
- Defect Activation: Sequential vacuum annealing was conducted at 800 °C (30 minutes) and 1100 °C (90 minutes) to activate the SnV centers.
- Nanostructure Fabrication: Nanopillars and mesas (500 nm tall) were fabricated using e-beam lithography, a SixNy hard mask, and reactive ion etching (RIE) using SF6, CH4, and N2 gases.
- Electrode Metalization: Parallel electrodes (4 ”m wide, 1 ”m gap) were defined via e-beam lithography and metal liftoff. The metal stack consisted of 5 nm Titanium (Ti) followed by 30 nm Gold (Au), deposited via e-beam evaporation.
- Optical Characterization: Photoluminescence Excitation (PLE) measurements were performed at cryogenic temperatures (~5 K) while applying DC voltage (up to ±150 V) to the electrodes to measure the Stark shift.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is uniquely positioned to supply the high-quality diamond materials and custom fabrication services required to replicate and advance this research in Stark tuning of Group-IV color centers.
| Research Requirement | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| High-Purity Substrate | Optical Grade Single Crystal Diamond (SCD) | SCD material with extremely low nitrogen content, minimizing background defects and ensuring the low-strain environment critical for achieving narrow SnV linewidths (194 MHz). |
| Custom Dimensions & Thickness | Plates/Wafers up to 125 mm; Thickness up to 500 ”m | We provide custom-sized SCD plates, ensuring optimal geometry for subsequent ion implantation and large-scale nanophotonic device fabrication. |
| Electrode Integration | Custom Metalization Services (Ti/Au, Pt, Pd, W, Cu) | We offer the precise 5 nm Ti / 30 nm Au metal stack used in the experiment, guaranteeing reliable, high-quality ohmic contacts necessary for applying high electric fields (up to 50 MV/m) without failure. |
| Surface Quality for Nanostructuring | Ultra-Low Roughness Polishing (Ra < 1 nm) | Our SCD surfaces are polished to Ra < 1 nm, which is essential for minimizing fabrication-induced strain and inhomogeneous broadening during the creation of 500-nm tall nanopillars. |
| Defect Engineering Support | Consultation on Implantation & Annealing | Our PhD engineering team assists researchers in optimizing material selection and post-growth processing recipes (e.g., 1100 °C vacuum annealing) to maximize SnV center yield and spectral stability. |
| Global Supply Chain | Global Shipping (DDU default, DDP available) | We ensure rapid and secure delivery of sensitive SCD materials to international research facilities, supporting time-critical quantum projects. |
Applicable Materials
Section titled âApplicable MaterialsâOptical Grade Single Crystal Diamond (SCD) is required to replicate the low-strain, high-purity environment necessary for SnV centers. For applications requiring high thermal conductivity or integration with complex electronics, 6CCVD can also provide Polycrystalline Diamond (PCD) substrates up to 125 mm in diameter.
Customization Potential
Section titled âCustomization Potentialâ6CCVD offers custom metalization services, including the specific Ti/Au stack used for the high-voltage electrodes, as well as precision laser cutting for unique chip dimensions required for nanophotonic integration. We can also supply substrates pre-thinned to specific depths, optimizing the material for subsequent ion implantation targeting shallow SnV centers (~90 nm).
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in defect engineering and can assist researchers in optimizing material selection, surface preparation, and post-growth annealing recipes for maximizing SnV center yield and minimizing strain in similar Stark Effect Tuning projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Group-IV color centers in diamond have attracted significant attention as solid-state spin qubits because of their excellent optical and spin properties. Among these color centers, the tin-vacancy (Sn-V<sup>-</sup>) center is of particular interest because its large ground-state splitting enables long spin coherence times at temperatures above 1 K. However, color centers typically suffer from inhomogeneous broadening, which can be exacerbated by nanofabrication-induced strain, hindering the implementation of quantum nodes emitting indistinguishable photons. Although strain and Raman tuning have been investigated as promising tuning techniques to overcome the spectral mismatch between distinct group-IV color centers, other approaches need to be explored to find methods that can offer more localized control without sacrificing emission intensity. Here, we study the electrical tuning of Sn-V<sup>-</sup> centers in diamond via the direct-current Stark effect. We demonstrate a tuning range beyond 1.7 GHz. We observe both quadratic and linear dependence on the applied electric field. Further, we also confirm that the tuning effect we observe is a result of the applied electric field and is distinct from thermal tuning due to Joule heating. Stark tuning is a promising avenue toward overcoming detunings between emitters and enabling the realization of multiple identical quantum nodes.