Large-area inverse opal structures in a bulk chalcogenide glass by spin-coating and thin-film transfer

• Published in: Optical materials 2013-12, Vol.36 (2), p.390-395
• Main Authors: Kohoutek, T., Orava, J., Strizik, L., Wagner, T., Greer, A.L., Bardosova, M., Fudouzi, H.
• Format: Article
• Language: English
• Subjects: Chalcogenide glasses; Chalcogenides; Disks; Ellipsometry; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Glass; Inverse opal; Monolayers; Nanostructure; Optical materials; Optical properties; Optics; Photonic bandgap materials; Photonic structures; Photonics; Physics; Reflectance; Solvents; Spin-coating; Thin films
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2013.09.026

•Large-area inverse-opal structures were prepared in a bulk chalcogenide glass.•Spin-coating is used to infill silica opal which is then transferred on bulk glass.•Inverse-opal structures stop-bands are consistent with effective refractive index.•Low-cost deposition and quality control of inverse structures in the glass is done. Large (cm×cm), uniform-thickness areas of an inverse-opal photonic crystal and an inverse-opal monolayer were fabricated in a high-refractive-index As30S70 chalcogenide glass. We have developed an effective low-cost, solution-based process for fabrication of photonic structures in chalcogenide glass from silica-colloidal-crystal thin-film templates (multi- and monolayer). The chalcogenide-glass solution is spin-coated over the silica-opal film template and the infilled composite structure (chalcogenide/opal) is then lifted-off and transferred onto the chalcogenide-glass disc at 225°C, followed by removal of the template in hydrofluoric acid. The extra step introduced in this work (lift-off and transfer) allows a reproducible and large-area structure to be fabricated on a bulk chalcogenide glass. Complete infilling of the silica template is possible due to the nano-colloidal nature (particle size 2–8nm) of the chalcogenide-glass solution and effective solvent release from the spin-coated chalcogenide film during post-annealing. The resulting chalcogenide-glass inverse-opal multilayer exhibits a Bragg peak at 670nm with a reflectance 70%, while the inverse-opal monolayer shows anti-reflectance behaviour