Preparation of CuO-Ta<SUB>2</SUB>O<SUB>5</SUB> Composites Using a Simple Co-Sputtering Method
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2015-01-01 |
| Journal | Journal of Materials Science and Chemical Engineering |
| Authors | Kenta Miura, T. Osawa, Yuya Yokota, Zobaer Hossain, Osamu Hanaizumi |
| Institutions | Kiryu University, Gunma University |
| Citations | 4 |
| Analysis | Full AI Review Included |
Technical Analysis and Documentation for 6CCVD
Section titled “Technical Analysis and Documentation for 6CCVD”Executive Summary
Section titled “Executive Summary”The analyzed research details the preparation of novel CuO-Ta₂O₅ composite films using a simple radio-frequency (RF) magnetron co-sputtering and subsequent high-temperature annealing method, targeting advanced optoelectronic and sensor applications.
- Novel Material Synthesis: First-time synthesis of CuO-Ta₂O₅ composite films via simple co-sputtering, using a Ta₂O₅ disc and a CuO pellet target setup.
- Phase Transformation: Films annealed at 600°C remained primarily amorphous, exhibiting a sharp photoluminescence (PL) peak at 450 nm (attributed to Cu2+ transition). Films annealed at 700°C, 800°C, and 900°C transformed into the desirable tetragonal CuTa₂O₆ phase.
- High-Temperature Requirement: Successful synthesis of high-quality, defect-free CuTa₂O₆ requires annealing temperatures exceeding 900°C, demanding highly robust substrate materials.
- Target Application: The resulting CuTa₂O₆ films are highly suitable for integration into chemisorptions conductometric gas sensors, leveraging the material’s structural and electrical properties.
- Engineering Relevance: The requirement for precise film cutting (diamond-wire saw) and high-temperature processing underscores the need for ultra-hard, thermally stable substrates and specialized material processing capabilities.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Sputtering Method | RF Magnetron Co-Sputtering | N/A | ULVAC SH-350-SE System |
| Ta₂O₅ Target Diameter | 100 | mm | Disc, 99.99% Purity |
| CuO Pellet Diameter | 20 | mm | Pellet placed on Ta₂O₅ erosion area |
| RF Power | 200 | W | Supplied to the target |
| Gas Flow (Ar) | 15 | sccm | Processing gas |
| Deposition Pressure | ~5.4 x 10-4 | Torr | Pressure during sputtering |
| Substrate Used | Fused-silica plate | 1 mm | Not heated during sputtering |
| Annealing Temperature Range | 600 - 900 | °C | Annealed in ambient air |
| Annealing Time | 20 | min | Standard duration for rare-earth doped Ta₂O₅ films |
| PL Excitation Wavelength (λ) | 325 | nm | He-Cd Laser |
| Sharp PL Peak Wavelength | ~450 | nm | Observed only in 600°C (amorphous) film, attributed to Cu2+ |
| Desired Phase Structure | Tetragonal CuTa₂O₆ | N/A | Observed ≥ 700°C annealing |
| Sensor Application | Chemisorptions conductometric | N/A | Target use for CuTa₂O₆ phase |
Key Methodologies
Section titled “Key Methodologies”The composite films were fabricated and characterized using the following controlled sequence:
- Target Setup: A 20 mm diameter CuO pellet (99.9% purity) was physically placed onto the erosion area of a 100 mm diameter Ta₂O₅ disc (99.99% purity) target.
- Co-Sputtering Deposition:
- RF power (200 W) was supplied to the target assembly.
- Ar gas flow was set to 15 sccm.
- The chamber pressure was maintained at approximately 5.4 x 10-4 Torr.
- Films were deposited onto unheated 1 mm thick fused-silica substrates.
- Sample Preparation: The as-deposited film was cut into four specimens using a diamond-wire saw.
- Thermal Annealing (Crystallization):
- The four specimens were individually annealed in an electric furnace for 20 minutes in ambient air at controlled temperatures: 600°C, 700°C, 800°C, and 900°C.
- Characterization:
- X-Ray Diffraction (XRD) was used to confirm the crystalline phase transformation from amorphous (600°C) to tetragonal CuTa₂O₆ (≥ 700°C).
- Photoluminescence (PL) spectra were recorded using a He-Cd laser (λ = 325 nm) to evaluate defect states and transition characteristics (e.g., the sharp 450 nm peak for Cu2+).
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD provides the specialized diamond materials and precision engineering services necessary to replicate this co-sputtering process on advanced platforms and enhance the performance of the final CuTa₂O₆ gas sensor devices.
Applicable Materials for Replication and Enhancement
Section titled “Applicable Materials for Replication and Enhancement”The requirement for high-temperature stability (up to 900°C and potentially higher) combined with applications in sensitive optoelectronics and gas sensors makes 6CCVD diamond a superior choice over fused-silica substrates.
| Requirement/Application | 6CCVD Material Recommendation | Material Justification |
|---|---|---|
| High-T Annealing Substrates | Optical Grade SCD (0.5 mm - 1 mm) | Extreme thermal stability and unmatched thermal conductivity eliminate T-induced stress or warping observed in silica, crucial for minimizing defects at ≥ 900°C annealing. |
| Conductometric Gas Sensors | Heavy Boron-Doped (BDD) PCD/SCD | BDD diamond offers excellent conductivity, corrosion resistance, and stable operation across wide temperature ranges, serving as a highly robust electrode or integrated heating element for conductometric sensing. |
| Optoelectronic Integration | High Purity SCD (Thickness 0.1 µm - 500 µm) | Provides a wide bandgap, superior transparency across UV/Visible/IR, and excellent lattice foundation for high-quality thin film epitaxy (though Ta₂O₅ is polycrystalline/amorphous here, SCD guarantees substrate stability). |
Customization Potential for Sensor Integration
Section titled “Customization Potential for Sensor Integration”6CCVD’s internal processing capabilities directly address the technical requirements cited in this research:
- Precision Substrate Sizing: The researchers used a diamond-wire saw to cut their films. 6CCVD offers in-house precision laser cutting services to achieve custom dimensions for plates/wafers up to 125 mm, ensuring exact form factors for device integration.
- Surface Preparation: For advanced thin-film deposition required for high-performance optoelectronics or sensors, 6CCVD provides ultra-smooth polishing services, guaranteeing an SCD surface finish of Ra < 1 nm or an inch-size PCD surface finish of Ra < 5 nm.
- Custom Metalization: For creating reliable ohmic contacts essential for conductometric gas sensors, 6CCVD offers extensive in-house metalization services including Au, Pt, Pd, Ti, W, and Cu deposition, customized to specific sensor layer designs.
Engineering Support
Section titled “Engineering Support”6CCVD’s in-house PhD engineering team can assist researchers in selecting the optimal MPCVD diamond material—whether it is high-purity Single Crystal Diamond (SCD) for optical applications, or Boron-Doped Diamond (BDD) for active electrodes—to replicate or extend this research into high-performance chemisorptions conductometric gas sensors projects. Our team provides global support, ensuring secure, timely delivery (DDU default, DDP available) of tailored diamond solutions worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
We prepared CuO-Ta2O5 composite films using our simple co-sputtering method for the first time. Four specimens were prepared from an as-deposited CuO-Ta2O5 sample by cutting it using a diamond- wire saw, and the specimens were subsequently annealed at 600°C - 900°C. The X-ray diffraction and photoluminescence (PL) of the annealed specimens were evaluated. The CuO-Ta2O5 film annealed at 600°C seemed to be primarily amorphous phase, and a sharp PL peak at a wavelength of 450 nm, due to the existence of Cu2+, was observed from the film. In contrast, the CuO-Ta2O5 films annealed at 700°C, 800°C, and 900°C seemed to be tetragonal CuTa2O6 phases. We expect that good-quality CuTa2O6 films can be obtained using our very simple co-sputtering method and subsequent annealing above 900°C. Such CuTa2O6 films can be used in chemisorptions conductometric gas sensors.