This technology is a novel method for producing near-atomically smooth, porous alumina thin films by spin coating, in ambient conditions, using aqueous precursors. By utilizing this method, the refractive index of the alumina thin film is tunable from 1.56 to 1.26 by the introduction of a nonionic surfactant in the aqueous precursors. At 900 ºC the porous framework remains intact. These films exhibit remarkable thermal stability, even as they start to crystallize at 900 ºC into the γ-phase. The porosity of the films, and thereby the refractive index, was shown to be controlled by the amount of surfactant in the precursor. Film thickness is also tunable, retaining nearly the same refractive index; this kind of control allows the thin-film precursor to be tailored for a wider range of use cases.
Features & Benefits
- Tunable index of refraction
- Aqueous precursors
- Atomically smooth
- Thermal stability to high temps (<1000°C)
- Anti-reflective coatings
- Dielectric thin films
- Scratch protection
Background of Invention
Typically, high quality thin films are produced via vacuum-based techniques, though the nature of this technique makes it difficult to produce porous films. In lieu of vacuum techniques, solution processing is a low-energy alternative to thin-film deposition. To manufacture porous thin films by solution processing, sol—gel precursors have received much attention. However, these precursors foster nanoparticle formation due to their highly reactive ligands, typically yielding rough, non-continuous films. Therefore, there remains a need for a method to produce porous and atomically smooth high quality films.
Ready for licensing and development
Provisional patent application filed