Microstructural and optical properties of nanocrystalline undoped zirconia thin films prepared by pulsed laser deposition

The zirconium oxide (ZrO₂) thin films are deposited on Si (100) and quartz substrates at various substrate temperatures (room temperature–973 K) at an optimized oxygen partial pressure of 3×10^?2 mbar using pulsed laser deposition technique. The effect of substrate temperature on microstructural, optical and mechanical properties of the films is investigated. The X-ray diffraction studies show that the films deposited at temperatures ≤773 K are monoclinic, while the films deposited at temperatures ≥873 K show both monoclinic and tetragonal phases. Tetragonal phase content increases with the increase of substrate temperatures. The surface morphology and roughness are investigated using atomic force microscope in contact mode. The optical properties of the films show that the refractive indices (at 550 nm) are found to increase from 1.84 to 2.35 as the temperature raises from room temperature (RT) to 973 K. Nanoindentation measurements show that the hardness of the films is 11.8 and 13.7 GPa for the films deposited at 300 and 973 K, respectively.