Luminescent and morphological characteristics of Al₂O₃:Tb films deposited by spray pyrolysis using acetylacetonates as precursors

Terbium-doped aluminum oxide films (Al₂O₃:Tb) were deposited by spray pyrolysis technique using aluminum and terbium acetylacetonates as precursors at temperatures up to 600°C. Room temperature cathodoluminescent and photoluminescent characteristics of the films have been studied as a function of the deposition parameters such as doping concentrations and substrate temperature. The observed emission has the spectral characteristics typical of radiative transitions among the electronic energy levels associated with the Tb³⁺ ion. Ultraviolet-visible transmission measurements show that the films are highly transparent in the visible region (a percent transmittance above 88% is observed). Atomic force microscopy measurements indicate that the surface of the films is very flat, showing an average surface roughness of 14 Å or less. The chemical composition of the films as determined by energy dispersive spectroscopy is also reported.