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 x 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 similar to 2.1-3.6 nm. The PL studies of the films showed a broad peak at similar to 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 x 10(-7) A/cm(2) 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.