Photo- and cathodoluminescence of Eu3+ or Tb3+ doped CaZrO3 films prepared by pulsed laser deposition

Luminescent films of Eu3+ or Tb3+ doped CaZrO3 were epitaxially grown on SrTiO3 or LaAlO3 (001) single crystal substrates by pulsed laser deposition (PLD). They showed a high transmittance in the visible region and a smooth surface. Uniform red photoluminescence (PL) was observed from Eu3+ 5% doped films, and blue and green PL was observed from Tb3+ 0.5% and 5% doped films, respectively. These PL spectra of the films turned out to be very similar to those of the powder samples. Practically, it has to be noticed the use of a LaAlO3 substrate is necessary for intense blue luminescence for Tb3+ 0.5% doped films to avoid optical absorption of emitted light by the SrTiO3 substrate. The cathodoluminescence (CL) spectra of the red and green luminescent films were almost the same as those PL spectra. In contrast, blue CL was significantly enhanced in CL compared to PL. This was attributed to the shorter lifetime of the 5D3-7FJ transitions and many excited electron-hole pairs, which were generated rapidly on high energy electron irradiation.