Research and Application Progress of Boron-doped Diamond Films
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-07-12 |
| Journal | Highlights in Science Engineering and Technology |
| Authors | Guangqiang Hou, Jingyan Ye, Jiaxing Han, Zhenghang Han, Xiang Yu |
| Institutions | China University of Geosciences (Beijing) |
| Citations | 4 |
| Analysis | Full AI Review Included |
Research and Application Progress of Boron-doped Diamond Films (BDD)
Section titled âResearch and Application Progress of Boron-doped Diamond Films (BDD)âExecutive Summary
Section titled âExecutive SummaryâBoron-doped diamond (BDD) films are critical materials developed to overcome the insulating nature of pure diamond (resistivity up to 1012 Ω·m), enabling broad applications in electrochemistry and semiconductors.
- Core Value Proposition: BDD achieves electrical conductivity (acting as a conductor, semiconductor, or superconductor) by incorporating small Boron (B) atoms into the diamond lattice, maintaining the diamondâs superior mechanical and chemical stability.
- Electrochemical Superiority: BDD electrodes exhibit a wide potential window, very high oxygen precipitation potential, low background current, and excellent chemical inertness, making them superior to common metal electrodes.
- Preparation Methods: The primary methods are Chemical Vapor Deposition (CVD)âspecifically Microwave Plasma CVD (MW-PCVD) for high qualityâand Ion Implantation, followed by annealing.
- Wastewater Treatment: BDD is widely used as an anode material for electrochemical oxidation, generating free radicals (OH) to decompose toxic organic pollutants into harmless CO2 and H2O.
- Sensing and Detection: BDD electrodes are ideal for detecting trace organic compounds and biomolecules (e.g., amino acids, nucleobases) due to their good biocompatibility and low background currents.
- Structural Integrity: B doping does not substantially alter the fundamental face-centered cubic, sp3-hybridized structure of the diamond crystal.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Pure Diamond Resistivity | up to 1012 | Ω·m | Insulating property |
| C-C Bond Length | 0.154 | nm | Ortho-tetrahedral structure |
| C-C Bond Angle | 109°28â | degrees | Ortho-tetrahedral structure |
| C-C Bond Energy | 347 | kJ/mol | Covalent bond strength |
| Lattice Constant (298 K) | 0.356683 | nm | Face-centered cubic structure |
| Sound Wave Propagation Speed | up to 18.2 | km/s | Diamond crystal elasticity |
| UV Transmittance Range | from 0.22 | ”m | Vacuum UV band |
| Optimal B Doping Concentration | 2 | g/L | Maximizing potential window (using B2O3 source) |
| Diamond Bandgap Width | 5x | Silicon bandgap | Semiconductor potential |
Key Methodologies
Section titled âKey MethodologiesâBDD films are primarily prepared using doping techniques applied to diamond substrates or during growth. High-temperature and high-pressure (HTHP) methods are mainly reserved for single-crystal substrate growth, not general doping.
1. Chemical Vapor Deposition (CVD) Doping
Section titled â1. Chemical Vapor Deposition (CVD) DopingâCVD is the most common method, utilizing gaseous precursors (e.g., methane, hydrogen) and a boron source (e.g., trimethyl borate).
| Method | Advantages | Disadvantages |
|---|---|---|
| HFVCD (Hot Filament) | Easy to operate, simple equipment, suitable for large size BDD electrodes. | Poor stability, easy contamination, cannot deposit high-quality films. |
| MW-PCVD (Microwave Plasma) | No electrode discharge contamination, wide operating pressure range, high plasma density, uniform large-volume plasma. | High equipment price, difficult to deposit large area films, low deposition rate. |
2. Ion Implantation Method
Section titled â2. Ion Implantation MethodâThis method injects boron ions directly into an already prepared diamond film using electric field acceleration.
- Process Steps:
- Preparation of pure diamond film substrate.
- Injection of boron ions using high-energy acceleration.
- Annealing is required to remove the severe surface damage caused by high-energy ions and prevent graphitization.
- Challenges: The tight carbon-carbon bond makes long-distance diffusion difficult, and high-energy injection damages the surface structure.
- Mitigation: Multiple ion implantation/one-annealing cycle processes are typically employed to reduce surface damage, especially for P-type semiconductor preparation.
Commercial Applications
Section titled âCommercial ApplicationsâBDD films are highly valued for their robust physical properties combined with excellent electrochemical performance.
1. Electrochemistry and Electrode Materials
Section titled â1. Electrochemistry and Electrode Materialsâ- Electrocatalyst Carriers: Used in advanced electrode designs (e.g., rotating ring-disk electrodes) due to chemical stability, low background currents, and wide solvent potential windows.
- Harsh Environment Sensing: Used in electroconductive water content sensors operating under harsh downhole conditions, optimized for resistance to erosion, abrasion, and electrochemical corrosion.
2. Wastewater Treatment (Anode Applications)
Section titled â2. Wastewater Treatment (Anode Applications)âBDD electrodes serve as highly efficient anodes for the decomposition of toxic and non-biodegradable organic compounds.
- Mechanism: Direct oxidation or indirect oxidation via the generation of strong active oxidizing substances, primarily hydroxyl radicals (OH).
- Target Wastes: Municipal wastewater, hospital wastewater, petrochemical wastewater, printing and dyeing effluent, and pharmaceutical waste.
- Disinfection: Used in BDD electrode systems for ozone disinfection, offering high efficiency, environmental safety, and chemical stability, overcoming limitations of traditional methods (UV, chlorine).
3. Trace Compound Detection and Biosensing
Section titled â3. Trace Compound Detection and BiosensingâBDDâs inert surface and biocompatibility make it ideal for sensitive analytical applications.
- Biomolecule Detection: Used for the amperometric determination of amino acids, peptides, proteins, nucleobases, nucleases, nucleotides, and DNA/RNA.
- Pharmaceutical Analysis: Applied in the highly sensitive determination of compounds like atropine and cefepime in biological fluids and dosage forms.
4. Advanced Materials and Electronics
Section titled â4. Advanced Materials and Electronicsâ- Semiconductors: Potential for high breakdown voltage devices, leveraging the wide bandgap (5x that of silicon).
- Optoelectronics: Applications in making capacitors and optoelectronic components due to tunable conductivity.
View Original Abstract
Thanks to its unique structure, diamond has many excellent properties, such as high hardness, low birefringence, high thermal conductivity, good chemical stability, etc., but pure diamond has extremely high resistivity (up to 1012 멉m ), which is an insulator, so it is usually doped to expand the application of diamond in the electrochemical field. B atoms have a very small radius, which is an ideal material for doping diamond, and B-doped diamond has good electrical conductivity. In this paper, on the basis of introducing the phase composition and structure of boron-doped diamond (BDD) film, the common methods for preparing BDD film are analyzed, and the application status and prospect of its application in electrochemistry and other fields are summarized.