High Refractive Index Ti₃O₅ Films for Dielectric Metasurfaces

Ti₃O₅ films are deposited with the help of an electron beam evaporator for their applications in metasurfaces. The flm of subwavelength (632 nm) thickness is deposited on a silicon substrate and annealed at 400°C. The ellipsometry result shows a high refractive index above 2.5 with the minimum absorption coefcient in the visible region, which is necessary for high efciency of transparent metasurfaces. Atomic force microscopy analysis is employed to measure the roughness of the as-deposited flms. It is seen from micrographs that the deposited flms are very smooth with the minimum roughness to prevent scattering and absorption losses for metasurface devices. The absence of grains and cracks can be seen by scanning electron microscope analysis, which is favorable for electron beam lithography. Fourier transform infrared spectroscopy reveals the transmission and re?ection obtained from the flm deposited on glass substrates. The as-deposited flm shows high transmission above 60%, which is in good agreement with metasurfaces.