Tungsten Oxide, WO3
Tungsten oxide (WO3) is a wide-bandgap n-type semiconductor oxide prized for its strong, reversible electrochromic response and its chemical and thermal stability. Supplied by Infinita Materials as a high-purity ceramic sputtering target, WO3 enables direct, single-step reactive or non-reactive deposition of dense, stoichiometric tungsten oxide thin films without the process drift common to reactive sputtering from a metallic tungsten target. It is the material of choice for smart-window electrochromics, gas sensing layers, and photoelectrochemical and photocatalytic thin-film stacks.
| Purity (%) : | >99.9 |
| Dimensions : | Dia. 1”, Thick. 0.125” Dia. 2”, Thick. 0.25” |
Introduction to Tungsten Oxide
Tungsten Trioxide (WO₃) is a wide-bandgap semiconductor with a corner-sharing WO₆ octahedral structure and multiple temperature-dependent crystal phases. Its open framework can reversibly accommodate small ions such as H⁺ and Li⁺, enabling strong electrochromic and ion-insertion properties. WO₃ is thermally stable, chemically resistant, and has a melting point near 1473°C. Sputtering directly from WO₃ targets provides better control of film stoichiometry and oxygen content than reactive sputtering from metallic tungsten. Sputtered WO₃ films are widely used in smart windows, automotive mirrors, gas sensors, photoelectrochemical devices, and photovoltaic research, where consistent optical and electrical performance is essential.
FAQs
Question: Is WO3 sputtered with RF or DC power?
Answer: Because WO3 is a semiconducting ceramic oxide, RF or pulsed-DC magnetron sputtering is most common for direct deposition from the oxide target. Reactive DC sputtering from a metallic tungsten target in an Ar/O2 atmosphere is an alternative route, but it is more prone to target poisoning and stoichiometry drift than sputtering the oxide directly.
Question: What sizes and shapes are available?
Answer: Standard stock includes 1in and 2in diameter discs (0.125in and 0.25in thick); 3in-6in diameter, rectangular, rotary/cylindrical, and step-target geometries up to 820mm are available on a custom basis for production-scale coating lines.
Question: What is the typical lead time for a custom WO3 target order?
Answer: Standard catalog sizes typically ship from stock or within a short standard lead time; custom sizes, high-purity grades, and bonded assemblies require additional fabrication and QC time. Contact Infinita Materials with target dimensions and purity grade for a specific lead-time quote.
Introduction to Tungsten Oxide
Tungsten Trioxide (WO₃) is a wide-bandgap semiconductor with a corner-sharing WO₆ octahedral structure and multiple temperature-dependent crystal phases. Its open framework can reversibly accommodate small ions such as H⁺ and Li⁺, enabling strong electrochromic and ion-insertion properties. WO₃ is thermally stable, chemically resistant, and has a melting point near 1473°C. Sputtering directly from WO₃ targets provides better control of film stoichiometry and oxygen content than reactive sputtering from metallic tungsten. Sputtered WO₃ films are widely used in smart windows, automotive mirrors, gas sensors, photoelectrochemical devices, and photovoltaic research, where consistent optical and electrical performance is essential.
Key Properties of Tungsten Oxide
| Property | Value | Significance |
|---|
| Chemical formula | WO3 | Fully oxidised, stoichiometric ceramic target; avoids the metal-to-oxide transition instability of reactive W sputtering |
| Crystal structure | Monoclinic (gamma-WO3) at room temperature; ReO3-type corner-sharing WO6 octahedral network | Open octahedral channels enable reversible ion/electron insertion, the basis of electrochromic switching |
| Molar mass | ~231.84 g/mol | Used for stoichiometric process calculations and deposition rate modelling |
| Density (bulk) | ~7.16 g/cm3 | Baseline for target mass/thickness specification and expected sputtered film packing density |
| Optical bandgap | ~2.6-3.2 eV (amorphous to nanocrystalline range) | Wide bandgap gives high visible transparency in the bleached state, essential for smart-window and display applications. |
| Electrical character | Intrinsic n-type semiconductor; conductivity rises sharply with oxygen sub-stoichiometry (WO3-x) | Governs choice of RF vs. reactive DC/pulsed-DC sputtering and the resulting film’s electrochromic vs. conductive behaviour |
| Melting point | ~1473 degrees C | High thermal stability supports target durability under sustained plasma bombardment. |
| Sputtering behavior | Ceramic oxide target; RF or pulsed-DC magnetron sputtering typically used; also deposited by reactive DC from a metallic W target | Direct oxide sputtering avoids target poisoning/arcing and gives more repeatable film stoichiometry than reactive processes. |
Types & Grades of Tungsten Oxide
Tungsten Oxide targets are offered in standard catalogue sizes and grades, with custom purity, density, and geometry available for OEM and R&D deposition systems.
| Grade / Form | Typical Purity | Key Features / Uses |
|---|
| Standard catalogue disc | 99.9% (3N) | 1in and 2 in diameter stock discs for R&D and process development; fastest lead time |
| High-purity grade | 99.99% – 99.999% (4N – 5N) | Reduced metallic and alkali contamination for electrochromic and photoelectrode films where trap states must be minimised |
| Large-format / custom | 99.9% – 99.99% | Rectangular and oversized round targets sized to production-scale in-line and glass-coating sputter systems |
| Rotary/cylindrical | 99.9% – 99.99% | Extended target life and uniform erosion for high-throughput architectural and automotive glass coating lines |
| Bonded assembly | 99.9% – 99.99% target on Cu or Al backing plate | Improves thermal dissipation and mechanical integrity for high-power sputtering of this ceramic oxide |
Applications of Tungsten Oxide
Sputtered films of Tungsten Oxide support demanding roles across research and production applications where this material’s specific structural, electronic, or optical properties are the key requirement.
| Industry | Application | Function |
|---|
| Architectural and automotive glass | Electrochromic smart windows and dimmable mirrors | Reversible ion insertion drives the coloration/bleaching that modulates visible and solar transmittance. |
| Consumer and automotive electronics | Electrochromic displays and anti-glare rearview mirrors | Provides low-power, non-emissive contrast switching |
| Gas sensing | NOx, H2, and NH3 chemi resistive and gasochromic sensors | Oxygen vacancy-dependent conductivity changes on gas adsorption give a measurable sensing signal |
| Renewable energy/photo electrochemistry | Photoanodes and interlayers for water-splitting and photocatalytic research cells | Bandgap and band-edge positions support visible-light photoactivity and charge transport. |
| Photovoltaics | Hole transport/interlayers in perovskite and thin-film solar cell stacks | High work function and transparency support efficient charge extraction with minimal optical loss |
| Optical coatings | High-refractive-index layers in multilayer optical and anti-reflective stacks | Stable, transparent wide-bandgap oxide with a tunable refractive index |
Why Partner with Infinita Materials?
- Technical Depth: in-house quality control with ICP-MS and XRF purity verification, density measurement, and full certificates of analysis on every target.
- Global Logistics: reliable supply from single R&D-scale targets to production-line volumes, with established international shipping.
- Responsive Support: direct access to materials engineers for grade, bonding, and geometry selection, and process-compatibility questions.
Infinita Materials fabricates Tungsten Oxide sputtering targets engineered to the purity, density, and geometry your deposition process requires. Whether the requirement is a standard catalogue target or a custom size, purity, or bonded assembly, our team can help match the right specification to your deposition system. Request a quote or speak with our technical team to discuss your target specification.
Frequently Asked Questions
Is WO3 sputtered with RF or DC power?
Because WO3 is a semiconducting ceramic oxide, RF or pulsed-DC magnetron sputtering is most common for direct deposition from the oxide target. Reactive DC sputtering from a metallic tungsten target in an Ar/O2 atmosphere is an alternative route, but it is more prone to target poisoning and stoichiometry drift than sputtering the oxide directly.
What sizes and shapes are available?
Standard stock includes 1in and 2in diameter discs (0.125in and 0.25in thick); 3in-6in diameter, rectangular, rotary/cylindrical, and step-target geometries up to 820mm are available on a custom basis for production-scale coating lines.
What is the typical lead time for a custom WO3 target order?
Standard catalog sizes typically ship from stock or within a short standard lead time; custom sizes, high-purity grades, and bonded assemblies require additional fabrication and QC time. Contact Infinita Materials with target dimensions and purity grade for a specific lead-time quote.
Tungsten Oxide, WO3
Used in Various Industries
Biomedical
Energy
Aerospace
Automotive
Healthcare
Electronics
