Micro-nanostructuring of ZrO2 sol-gel by optical and nanoimprint lithography on various substrate for optical applications

Abstract

Zirconium oxide (ZrO2) is an intensively studied and used material due to its many remarkable physical and chemical properties. The high performances of ZrO2 allows its use in many applications such as coatings against corrosion, wear and oxidation, optical applications, anti-counterfeiting, or in medical applications such as dental or prosthesis. There are many methods to synthesize ZrO2 among which we can mention reactive sputtering, chemical vapor deposition, atomic layer deposition. These techniques are well known in thin film deposition processes. However, they do not allow to easily structure the coatings to produce complex patterns (shapes, micro-nanostructures) on variable substrates in shape and size. Another process of elaboration of ZrO2 thin films is the sol-gel method. This technique makes possible the micro-nanostructuring of the films by optical and nanoimprint-based lithography. In this paper, the authors will describe how the ZrO2 sol-gel can be used to obtain both complex patterns (shapes, micro-nanostructures) by optical lithography (mask lithography, colloidal lithography) and by nanoimprint lithography. The authors will also show the possibility to use this versatile sol-gel and the associated structuring methods to structure complex patterns on variable substrates in their nature and geometry, as well as the possibility of using this process in optical applications. Preliminary results will be presented through several microstructured ZrO2 demonstrators obtained from the microstructuring process on sol-gel layers. The produced layers have been characterized by Raman spectroscopy, scanning electron microscopy, atomic force microscopy. The optical properties (transmittance, reflectance) have also been investigated and a study of the influence of a thermal treatment on the refractive index and thickness of the layer has been carried out.