Formation of Q‐Carbon Nanoballs and Nanodiamonds by Pulsed Laser Annealing of Patterned Polymer Structures
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2025-10-13 |
| Journal | Advanced Materials Interfaces |
| Authors | Sumeer Khanna, Kishan Kumawat, Roger J. Narayan |
| Institutions | North Carolina State University |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Patterned Q-Carbon and Nanodiamond Formation
Section titled “Technical Documentation & Analysis: Patterned Q-Carbon and Nanodiamond Formation”Executive Summary
Section titled “Executive Summary”This research introduces a highly controlled, non-equilibrium fabrication route for creating patterned Q-Carbon nanoballs and Nanodiamond (ND) crystallites, materials critical for next-generation semiconductor and quantum applications.
- Novel Fabrication Route: Utilizes Direct Laser Writing (DLW) / Two-Photon Polymerization (2PP), followed by thermal carbonization and Pulsed Laser Annealing (PLA) for rapid phase conversion.
- High sp³ Content: Achieved high-purity carbon allotropes with an sp³/sp² ratio ranging from 80-90% post-PLA, significantly higher than the initial carbonized phase (45-55%).
- Precise Nanostructure Control: Demonstrated size control, yielding Q-Carbon nanoballs (≈45-50 nm) and ultra-small Nanodiamond crystallites (≈3-5 nm).
- Quantum Confinement Observed: The 3-5 nm ND crystallites exhibited a characteristic Raman downshift to 1327 cm-1, confirming quantum confinement effects highly relevant for quantum sensing.
- Scalability and Substrate Versatility: Successfully patterned 2D thin films (down to 100 nm thickness) and 3D microstructures on standard semiconductor substrates (Si (100) and sapphire (0001)).
- Non-Equilibrium Processing: The use of nanosecond PLA (20 ns pulse duration) ensures ultrafast quenching and high undercooling, essential for the formation of metastable Q-Carbon and ND phases.
- Target Applications: The resulting high-density, patterned diamond structures are ideal for high-power electronics, thermal management, quantum sensors (NV centers), and biomedical devices.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Final sp³ Content (Q-C/ND) | 80-90 | % | Post-PLA, confirmed by Raman/XPS |
| Nanodiamond Crystallite Size | 3-5 | nm | Confirmed by HRTEM/STEM |
| Q-Carbon Nanoball Size | 45-50 | nm | Confirmed by HRTEM/STEM |
| Nanodiamond Raman Shift | 1327 | cm-1 | Downshift due to phonon confinement |
| PLA Laser Wavelength | 193 | nm | ArF Excimer Laser (UV) |
| PLA Pulse Duration | 20 | ns | Critical for achieving high undercooling |
| PLA Energy Density (Thick Films) | ≈0.8 | J cm-2 | Used for 3D structures (>1 µm) |
| Thin Film Thickness Range | 100-900 | nm | 2D patterned structures |
| Substrate Materials Used | Si (100), Sapphire (0001) | N/A | Standard semiconductor platforms |
| Carbonization Temperature | 540 | °C | Thermal annealing under Ar atmosphere |
Key Methodologies
Section titled “Key Methodologies”The patterned Q-Carbon and Nanodiamond structures were fabricated using a three-step process optimized for non-equilibrium phase transformation:
-
Direct Laser Writing (DLW) / Two-Photon Polymerization (2PP):
- Purpose: Fabrication of 2D and 3D polymeric structures (e.g., triangular rods) with high precision.
- Laser Source: Pulsed Near-Infrared (NIR) laser (λ = 932 nm).
- Substrates: Si (100) and sapphire (0001).
- Feature Size: Base footprint area of 150 µm x 150 µm.
-
Carbonization (Thermal Annealing):
- Purpose: Conversion of polymeric resin into amorphous/semi-crystalline carbon.
- Equipment: Tube furnace (GSL-1500X-OTF).
- Atmosphere: Inert Argon (Ar) gas (5 l/min flow) at ≈2 Torr pressure.
- Thermal Profile: 20 °C/min ramp rate, holding at 420 °C and 540 °C (5 min hold at each).
- Result: Carbonized structures exhibiting 45-55% sp³ content.
-
Pulsed Laser Annealing (PLA):
- Purpose: Ultrafast melting and quenching of carbonized structures to form Q-Carbon and Nanodiamonds.
- Laser Source: ArF Excimer Laser (UV, λ = 193 nm).
- Pulse Parameters: 20 ns duration, energy density optimized between 0.7 J cm-2 (thin films) and 0.8 J cm-2 (thick films).
- Mechanism: Controls undercooling, leading to the first-order phase transformation from liquid carbon to the highly metastable Q-Carbon and ND phases.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD is uniquely positioned to support and extend this research into patterned Q-Carbon and Nanodiamond structures, particularly for applications requiring high-purity diamond materials, custom dimensions, and specialized surface engineering.
Applicable Materials for Replication and Extension
Section titled “Applicable Materials for Replication and Extension”The research highlights the need for high-quality, high-purity carbon phases and the potential for doping (N and B) to create quantum sensors. 6CCVD provides the ideal starting materials:
| 6CCVD Material | Relevance to Research | Key 6CCVD Capability |
|---|---|---|
| Optical Grade SCD | Ideal substrate for high-purity ND/Q-Carbon growth and subsequent NV center formation for quantum computing/sensing. | SCD plates up to 500 µm thickness, Ra < 1 nm polishing. |
| Polycrystalline Diamond (PCD) | Cost-effective, large-area platform for scaling up patterned device fabrication (e.g., high-power electronics, thermal management). | Plates/wafers up to 125mm diameter, custom thickness up to 500 µm. |
| Boron-Doped Diamond (BDD) | Essential for replicating Q-Carbon’s reported BCS high-temperature superconductivity and for creating p-type diamond devices. | Custom doping levels available for both SCD and PCD. |
| Diamond Substrates | Provides robust, high-thermal conductivity platforms superior to Si or Sapphire for high-power applications. | Substrates available up to 10 mm thickness. |
Customization Potential
Section titled “Customization Potential”The success of this patterned fabrication route relies heavily on precise material dimensions and surface preparation. 6CCVD offers comprehensive customization services:
- Custom Dimensions: While the paper used small 150 µm features, 6CCVD can supply diamond wafers (PCD up to 125mm) or custom-cut SCD plates to any required size and shape, facilitating large-area processing.
- Precision Polishing: To ensure optimal surface quality for DLW/2PP and subsequent PLA, 6CCVD provides ultra-low roughness polishing:
- SCD: Ra < 1 nm.
- Inch-size PCD: Ra < 5 nm.
- Advanced Metalization: The paper’s applications (FETs, sensors) often require ohmic contacts or specialized interfaces. 6CCVD offers in-house metalization services, including: Au, Pt, Pd, Ti, W, and Cu deposition, tailored to specific device architectures.
Engineering Support
Section titled “Engineering Support”The formation of Q-Carbon and Nanodiamonds is highly dependent on precise thermal kinetics and undercooling control. 6CCVD’s in-house PhD team specializes in CVD diamond growth and material characterization, offering expert consultation to researchers working on similar projects:
- Material Selection: Assistance in selecting the optimal diamond grade (SCD purity, PCD grain size, BDD doping level) to maximize device performance in Quantum Sensing and High-Power Electronics.
- Process Optimization: Guidance on substrate preparation and interface engineering to enhance nucleation and control the resulting nanostructure size and orientation, critical for achieving specific quantum confinement effects (e.g., controlling the 3-5 nm ND size).
- Global Logistics: Reliable global shipping (DDU default, DDP available) ensures 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
Abstract 2D and 3D patterned structures of Q‐carbon nanoballs and nanodiamonds have been created by laser writing of polymers, carbonization, and pulsed laser annealing. Specifically, 2D and 3D patterns of polymeric structures have been prepared by using a direct‐laser‐writing (DLW) process involving two‐photon polymerization (2PP). These patterned structures are carbonized to create amorphous carbon structures in various 2D and 3D forms. The sp 3 /sp 2 ratio (%) of these carbonized structures ranged from 45-55%, as determined by Raman and XPS studies. These carbonized structures are turned into Q‐carbon nanoballs or nanodiamonds by controlling the undercooling during nanosecond laser melting and quenching. The laser‐annealed structures varied from crystalline graphite (onion‐like structures) to diamond to Q‐carbon with increasing undercooling. The size range (average) of nanoballs is determined to be ≈45-50 nm, and it is ≈3-5 nm for nanodiamonds. The laser‐annealed structures are characterized by Raman and XPS for their bonding characteristics and HRTEM/STEM (HAADF) for detailed structural characterization. The Raman spectrum from nanodiamonds exhibited a downshift to 1327 cm −1 as a result of phonon confinement. The Raman spectra from Q‐carbon nanoballs confirmed the characteristic double hump centered ≈1340 and 1500 cm −1 peaks.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2001 - Nanostructured Carbon for Advanced Applications