Optical and mechanical characterization of sol-gel thin films of ZrO2 stabilized with different Y2O3-doping mol%

Abstract

The influence of the molar proportion of Y2O3 dopant (3, 9, and 12 mol%) on the optical and mechanical properties of ZrO2 thin films was studied. For this purpose, the three types of deposited thin films were first characterized microstructurally by spectrophotometry, optical microscopy, scanning electron microscopy, and X-ray diffractometry, and then their optical properties were measured by spectrophotometry and their mechanical properties by nanoindentation. It was found that they all crystallize in the cubic phase, even for dopant contents that would not do so in bulk materials. It was also found that, with increasing Y2O3 dopant, the refractive index increases while the optical absorption and extinction coefficients, the hardness, and the elastic modulus decrease. These trends are due to the poorer crystallinity and greater distortion of the crystal lattice of YSZ thin films with increasing Y2O3 dopant. The results are especially relevant for applications which require certain conditions of reflection and absorption of light energy, while maintaining optimal mechanical properties.