Photochemical deposition, characterization and optical properties of thin films of ThO2

Abstract

Thorium oxide thin films were successfully prepared by direct UV irradiation of amorphous films composed of thorium(IV) β-diketonate precursor complexes on Si(100) and quartz substrates. The ThO2 films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and atomic force microscopy (AFM). The X-ray diffraction patterns showed that the films that annealed at T° below 550 °C were amorphous. The films that annealed at 550 °C and above exhibited a preferred orientation along the (111) plane. Both the as-photodeposited and annealed ThO2 films exhibited a good optical quality with transparency in the visible region better than 85%. Photoluminescence of ThO2 thin films was reversibly quenched when exposed to 60 ppm of CO at room temperature.