JOURNAL OF MATERIALS SCIENCE LETTERS 20, 2 0 0 1, 1799 – 1801 Preparation and characterization of Eu doped zirconia luminescent films synthesized by the pyrosol technique M. GARCIA-HIPOLITO Programa de Posgrado en Tecnolog´ıa Avanzada, CICATA-IPN, Legaria, M´ exico, DF E. MARTINEZ,O. ALVAREZ-FREGOSO Instituto de Investigaciones en Materiales, UNAM, A.P. 70-360 Coyoac´ an 04510 M ´ exico, DF E-mail: oaf@seridor.unam.mx C. FALCONY Departamento de F´ısica, CINVESTAV-IPN, Apdo. Postal 14-740, M´ exico D F. 07000. (In sabbatical leave at Dep. of Materials Science, ESFM-IPN) M. A. AGUILAR-FRUTIS Centro de Investigaci ´ on en Ciencia Aplicada y Tecnolog´ıa Avanzada, CICATA-IPN, Legaria, M´ exico, DF The pyrosol method is a well-known process for de- positing films [1, 2]. The main advantages of this tech- nique are its low cost, a high deposition rate, the pos- sibility to coat large areas, its ease of operation and the quality of the coatings obtained. This technique has been used to deposit successfully a variety of films such as oxides, sulfides and metals [1]. Zirconia has attracted much attention in science and technology be- cause its high melting temperature, high refractive in- dex, low thermal conductivity, hardness and corrosion barrier properties [3]. Furthermore these films are use- ful in corrosion resistance applications [4], as insulat- ing layers in very large scale integrated (VLSI) cir- cuits [5], for optical coatings [6], in buffer layers for high T c oxide superconductors [7], etc. There are also some studies on rare earth doped luminescent zirco- nia single crystals and powders [8–10]. The present contribution is devoted to the preparation and char- acterization of ZrO 2 : Eu photoluminescent (PL) and cathodoluminescent (CL) films synthesized by the py- rosol technique. To our best knowledge, there has been no report on luminescent coatings of ZrO 2 : Eu. These films can be applied in cathode ray tubes; color plasma displays panels, fluorescent lamps, vacuum fluores- cent display devices and electroluminescent flat panel displays. The experimental arrangement for pyrosol tech- nique has been presented elsewhere (2). The spray- ing solution was 0.05 M solution of zirconium oxi- chloride (ZrOCI 2 · 8H 2 O, Merck) in deionized water. Doping with Eu was achieved by adding EuCI 3 · 6H 2 O to the spraying solution in the range from 1 to 20 atomic percent (a/o) in relation to the Zr content in this solution. The carrier gas flow (filtered air) was 10 liter/min. The substrate temperature (T s ) during de- position was in the range from 250 to 500 ◦ C; the substrates used were fused quartz slides and (100) n-type silicon single crystals. The deposition time was adjusted (5–8 min) to get similar thickness on all samples studied. This thickness was approximately 5 μm as measured by a Sloan Dektak IIA stylus- type recording profilometer. The crystalline structure of the deposited films was analyzed by X-ray diffrac- tion (XRD), using a Siemens D-5000 diffractome- ter (λ = 1.5406 ˚ ACu k α ). The chemical composition of the films was measured using energy dispersive spectroscopy (EDS) with a Leica-Cambridge elec- tron microscope Mo. Stereoscan 440. The excitation (PLE) and emission PL spectra were obtained using a Perkin-Elmer LS50B fluorescence spectrophotome- ter. CL measurements were performed in a stainless steel vacuum chamber with a cold cathode electron gun (Luminoscope, model ELM-2 MCA, Relion Co.). The emitted light from the sample was coupled into an opti- cal fiber bundle leading to the spectrophotometer cited above. Results from X-ray diffractometry of the samples are shown in the Fig. 1. In this case, diffractograms for sam- ple ZrO 2 : Eu (20 a/o in solution) prepared at T s from 250 to 500 ◦ C are presented. The ZrO 2 : Eu coatings Figure 1 X-ray diffraction patterns for ZrO 2 : Eu 3+ films at six dif- ferent deposition temperatures, 250, 300, 350, 400, 450 and 500 ◦ C. (T = tetragonal zirconia, C = cubic zirconia). 0261–8028 C  2001 Kluwer Academic Publishers 1799