Microstructure, optical and dielectric properties of cerium oxide thin films prepared by pulsed laser deposition

Cerium oxide (CeO₂) thin films were deposited on Pt (111)/Ti/SiO₂/Si(100) substrates using pulsed laser deposition method at different temperatures such as, 300 K, 573 K and 873 K with 3 × 10⁻² mbar oxygen partial pressure. The prepared films were systematically investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and electrical measurement system. XRD analysis clearly showed improved crystallinity of CeO₂ films prepared at 573 and 873 K substrate temperatures. The AFM analysis indicated the uniform distribution of the nanocrystallites and dense structure with the roughness (RMS) of ~ 2.1–3.6 nm. The PL studies of the films showed a broad peak at ~ 366–368 nm, indicating the optical bandgap of 3.37–3.38 eV. The electrical property study showed minimum leakage current density of 2.0 × 10⁻⁷ A/cm² at 873 K, which was measured at 100 kV and this value was much lower than that of the CeO₂ film deposited at 300 K. The dielectric constants are increased and dielectric loss values decreased for the films with increasing substrate temperature.