Donor-acceptor pairs in wide-bandgap semiconductors for quantum technology applications
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-01-06 |
| Journal | npj Computational Materials |
| Authors | Anil Bilgin, Ian Hammock, Jeremy Estes, Yu Jin, Hannes Bernien |
| Institutions | University of Chicago |
| Citations | 14 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Donor-Acceptor Pairs in Wide-Bandgap Semiconductors
Section titled âTechnical Documentation & Analysis: Donor-Acceptor Pairs in Wide-Bandgap Semiconductorsâ6CCVD Material Science Analysis of npj Computational Materials (2024) 10:7
Executive Summary
Section titled âExecutive SummaryâThis research validates the potential of Donor-Acceptor Pairs (DAPs) in wide-bandgap semiconductors, specifically diamond (SCD) and silicon carbide (SiC), as a scalable platform for solid-state quantum technologies requiring long-range, optically controllable interactions.
- Core Value Proposition: DAPs exhibit large, optically switchable static electric dipole moments (predicted >25 Debye), enabling coherent dipole-dipole interactions scaling as 1/R3 over distances exceeding 10 nm.
- Material Focus: The study confirms that high-quality SCD diamond and 3C-SiC are suitable host materials for engineering these quantum defects.
- Optimal Defect Identification: B-P pairs in diamond and Al-N pairs in 3C-SiC are identified as the most promising candidates due to their shallow nature and significantly weaker electron-phonon coupling, allowing for experimentally resolvable Zero-Phonon Lines (ZPLs).
- Optical Control Mechanism: The ZPLs of DAPs demonstrate extraordinary sensitivity to applied electric fields (Stark shift tunability up to a few THz), confirming the feasibility of electronic and optical manipulation.
- Device Integration: The platform is compatible with integration into PIN heterostructures and requires precise nanofabrication, including custom metalization for electrostatic gates.
- 6CCVD Relevance: Replicating and advancing this research requires ultra-high purity, low-defect SCD diamond substrates and custom metalization capabilities, which are core offerings of 6CCVD.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the DFT calculations and experimental simulations detailed in the paper, highlighting critical parameters for quantum device engineering.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Host Materials | Diamond, 3C-SiC | N/A | Wide-bandgap semiconductors |
| Diamond Bandgap (HSE) | 5.37 | eV | Single Crystal Diamond (SCD) |
| 3C-SiC Bandgap (HSE) | 2.25 | eV | Silicon Carbide |
| Electric Dipole Moment (Predicted) | >25 | Debye | For DAPs (e.g., B-N m4, m5 in Diamond) |
| Long-Range Interaction Scale | >10 | nm | Dipole-dipole coupling (U ~ 1/R3) |
| Dipole-Dipole Interaction Strength | ~100 | MHz | At 100 nm distance (for 15 eĂ DAP) |
| ZPL Stark Shift Tunability | Up to a few | THz | B-N m5 shell in Diamond |
| Optimal Radiative Lifetime (Target) | ”s | N/A | Required for sufficient state manipulation |
| PL Spectra Calculation Temperature | 5 | K | Experimental simulation condition |
| CTL: NC (+/0) in Diamond (HSE) | EC - 1.80 | eV | Deep donor defect |
| CTL: AlSi (0/-) in 3C-SiC (HSE) | EV + 0.19 | eV | Shallow acceptor defect |
| Applied Electric Field (Gate) | kV cm-1 | N/A | Required for Stark shift control |
Key Methodologies
Section titled âKey MethodologiesâThe electronic structure and optical properties of DAPs were investigated using advanced first-principles computational methods, providing a robust theoretical foundation for experimental realization.
- Electronic Structure Calculation: Spin-polarized Density Functional Theory (DFT) was employed using the planewave pseudopotential method (Quantum Espresso).
- Functional Selection: Both the PBE semi-local functional and the HSE06 screened hybrid functional were utilized, with HSE06 providing results closer to experimental values, especially concerning defect geometries and lattice distortions.
- Supercell and Convergence: Calculations used 512-atom supercells (extrapolated up to 1000 atoms) with an energy cutoff of 90 Ry. Geometries were relaxed to a force threshold of 1 meV Ă -1.
- Dipole Moment Determination: Electric dipole moments were computed using the difference in polarization (ÎP) between ground and excited states, leveraging Maximally Localized Wannier Functions (MLWF) and Constrained DFT (CDFT).
- Zero-Phonon Line (ZPL) Analysis: ZPLs were calculated using constrained DFT as a function of donor-acceptor distance ($R_m$).
- Photoluminescence (PL) Spectra Modeling: PL spectra and electron-phonon coupling (Huang-Rhys factors) were simulated using the effective one-dimensional (1D) configurational coordinate (CC) approximation at a simulated temperature of 5 K.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful realization of this quantum science platform hinges on the availability of high-quality, engineered wide-bandgap materials and precise device integration capabilities. 6CCVD is uniquely positioned to supply the necessary SCD diamond substrates and customization services required to replicate and extend this research.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the low electron-phonon coupling and high crystal quality necessary for resolving sharp ZPLs, researchers require the highest grade SCD diamond.
- Optical Grade Single Crystal Diamond (SCD): Required for the host material in diamond-based DAPs (B-P pairs). 6CCVD supplies ultra-high purity SCD wafers, minimizing background defects that could interfere with long-range interactions.
- Capability Match: SCD plates available in custom dimensions, with thicknesses ranging from 0.1 ”m up to 500 ”m.
- Engineered SCD Substrates: The creation of substitutional defects (B, P, N) requires either controlled in situ doping or post-growth implantation into high-purity material. 6CCVD can provide:
- High-Purity SCD: Ideal for subsequent ion implantation of P or Al.
- Boron-Doped Diamond (BDD): For studies requiring controlled boron acceptor concentrations.
Customization Potential
Section titled âCustomization PotentialâThe paper emphasizes the need for integrating DAPs into functional heterostructures (e.g., PIN diodes) and controlling them via electrostatic gates, necessitating advanced fabrication services.
| Research Requirement | 6CCVD Customization Solution | Technical Specification |
|---|---|---|
| Substrate Size & Thickness | Custom plates and wafers for scalable device fabrication. | Plates/wafers up to 125 mm (PCD); Substrates up to 10 mm thick. |
| Surface Quality | Ultra-smooth surfaces critical for lithography and minimizing surface noise. | Polishing capability: Ra < 1 nm (SCD), Ra < 5 nm (Inch-size PCD). |
| Electrostatic Gate Fabrication | Custom metalization for creating PIN structures and high-voltage gates (kV cm-1 fields). | Internal metalization capability: Au, Pt, Pd, Ti, W, Cu deposition and patterning. |
| Defect Isolation | Precision laser cutting and shaping for creating isolated quantum structures. | Custom laser cutting and shaping services available. |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in the growth and characterization of CVD diamond for quantum applications. We offer authoritative professional support for projects focused on Solid-State Quantum Emitters and Dipolar Interactions.
- Material Selection: Assistance in selecting the optimal SCD grade (purity, orientation, doping level) to maximize the yield and coherence of engineered DAPs.
- Process Optimization: Consultation on integrating metalization layers and designing custom SCD thicknesses for optimal waveguide or cavity coupling, crucial for addressing and manipulating the DAPs.
- Global Logistics: Reliable global shipping (DDU default, DDP available) ensures prompt delivery of sensitive materials worldwide.
Call to Action: For custom specifications or material consultation regarding SCD substrates for long-range quantum interactions, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract We propose a quantum science platform utilizing the dipole-dipole coupling between donor-acceptor pairs (DAPs) in wide bandgap semiconductors to realize optically controllable, long-range interactions between defects in the solid state. We carry out calculations based on density functional theory (DFT) to investigate the electronic structure and interactions of DAPs formed by various substitutional point-defects in diamond and silicon carbide (SiC). We determine the most stable charge states and evaluate zero phonon lines using constrained DFT and compare our results with those of simple donor-acceptor pair (DAP) models. We show that polarization differences between ground and excited states lead to unusually large electric dipole moments for several DAPs in diamond and SiC. We predict photoluminescence spectra for selected substitutional atoms and show that while B-N pairs in diamond are challenging to control due to their large electron-phonon coupling, DAPs in SiC, especially Al-N pairs, are suitable candidates to realize long-range optically controllable interactions.