Mark Schwartzman - Video Lecture

Mark Schwartzman - Video Lecture

IVS-IPSTA 2020 Online Conference December 13, 2020

Nanomaterials, Thin films, and Surface Science
Morning Session

Session chair:
David Zitoun

Bar-Ilan University


Directly nanoimprinted sub-wavelength antireflective structures

Mark Schwartzman

Department of Material Engineering,
Ben-Gurion University of the Negev, Israel


Abstract


Sub-wavelength antireflective nanostructures are an attractive alternative to traditionally used antireflective thin films, due to their broadband and omnidirectional antireflective performance, as well as high environmental stability. Here, we demonstrate the novel approaches for the direct imprint chalcogenide glasses and organic polymers with subwavelength antireflective nanostructures. The first approach is based on a nanocomposite mold made of carbon nanotube matrix and Polydimethylsiloxane PDMS resin. To allow nanoimprint, the mold and the imprinted substrate are confined between two elastic membranes, pneumatically pressed against each other, and controllably radiated by an infrared bulb. By this method, only the interface between the mols and the substrate is heated above the glass transition temperature of the substrate, while the cold bulk of the surface is not deformed. In the second approach, the glass solution is applied onto the glass substrate by spin coating and baked. Here, we tuned the baking conditions to evaporate most of the solvent and obtained a “softened” glass film whose glass transition temperature is below that of pristine glass. In this case, a standard nanoimprint with PDMS mold was done by applying conductive heating and mechanical pressure, to yield the full pattern transfer with no damage to the substrate shape, similarly to in the first approach. In the third approach, a glass or a polymer is directly imprinted with a PDMS stamp soaked in a solvent that diffuses into the surface layer of the imprinted material and plasticizes it. Overall, our work presents several unconventional approaches for the direct maskless micro structuring of organic polymers chalcogenide glasses and paves the way to their numerous applications in the future optical components.