Photoluminescence of zirconia films with VUV excitation

Using synchrotron radiation as a source of VUV excitation, we examined the photoluminescence (PL) of zirconia (ZrO2) films prepared from zirconium propoxide by the sol-gel method at high temperature. X-ray diffraction (XRD) results reveal that ZrO2 films exhibit tetragonal, a mixture of tetragonal and monoclinic, and monoclinic phases at heating temperatures 700, 900 and 1100 deg. C, respectively. Upon VUV excitation, PL of a ZrO2 film in the tetragonal phase has a maximum at 390 nm, for which excitation is most efficient at 164 nm, near the energy gap of the tetragonal phase. PL emission in the monoclinic phase is characterized by a distinctive band at 475 nm, for which excitation is most efficient at 235 nm, near the energy gap of the monoclinic phase