Characterization of ZnAl2O4: Tb luminescent films deposited by ultrasonic spray pyrolysis technique

The preparation and characterization of terbium doped zinc aluminate photoluminescent films obtained by ultrasonic spray pyrolysis deposition process are described. Variations on doping concentrations in the start spraying solution and substrate temperatures were studied. XRD measurements on these films showed that the crystalline structure depends on the substrate temperature. For an excitation wavelength of 242 nm, all the photoluminescence spectra show peaks located at 488 nm, 546 nm, 589 nm and 621 nm. The photoluminescence intensity reaches values practically constant for the samples deposited at substrate temperatures higher than 400 °C. In this case, concentration quenching of the photoluminescence appears at doping concentrations greater than 0.93 atomic percent into the films. The surface morphology characteristics of the films deposited on glass and silicon substrates, as a function of the deposition temperature, are presented. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)