Infoscience

Poster

Nanostructured high refractive index titanium oxide films

Titanium oxide due to its optical properties, such as high refractive index, transparency to visible light and photocatalytic properties is being used in a large number of devices such as micro-optical elements and solar cells. The fabrication of TiO2 micro and nano-patterns however requires costly clean-room technology involving a number of fabrication steps. Alternatively titania can be prepared using low cost chemical solution deposition technique using sol-gel process. Sol-gel methods, on the other hand, suffer from high densification temperatures and therefore poorer performance. We present an advanced sol-gel process based on high titanium oxide content synthesis and its one-step patterning using nanoimprint lithography. TiO2 sol-gel films were prepared using titania precursors, titanium isopropoxide (90%) and silica precursor (10%) modified by organic moieties. TiO2 nano-particles were either added (Ø20nm) to the solution or formed in-situ (Ø5nm). The films up to 1 um were spin coated and imprinted at temperatures ranging from 80 to 130C. After this process, the films were cured with UV irradiation and shrank up to 50% leaving patterned areas free of cracks. The patterns from 50 nm to 2 um size and up to 300 nm deep were obtained. Refractive index of the films after UV irradiation increased from 1.6 to 2.1. Directly patternable and UV curable, crack-free and high purity TiO2 films up to 0.5 um thick are suitable for the fabrication of high efficiency micro-components.

Fulltext

  • There is no available fulltext. Please contact the lab or the authors.

Related material