The effect of different gas atmospheres on the structure, morphology and photoluminescence properties of pulsed laser deposited Y₃(Al,Ga) ₅O₁₂:Ce³⁺ nano thin films

Luminescent properties of Y₃(Al,Ga)₅O ₁₂:Ce³⁺ phosphor powder and thin films were obtained. The phosphor powder was used as target material for Pulsed Laser Deposition (PLD) of the thin films in the presence of different background gases. Excitation peaks for the powder were obtained at 439, 349, 225 and 189 nm and emission peaks at 512 and 565 nm. X-ray diffraction indicated that better crystallization took place for films deposited in a 20 mTorr O₂ atmosphere. Atomic force microscope revealed an RMS value of 0.7 nm, 2.5 nm and 4.8 nm for the films deposited in vacuum, O₂ and Ar atmospheres, respectively. The highest PL intensity was observed for films deposited in the O₂ atmosphere. A slight shift in the wavelength of the PL spectra was obtained for the thin films due to a change in the crystal field. The thickness of the films varied from 120 nm to 270 nm with films deposited in vacuum having the thin layer and those in Ar having the thick layer. The stoichiometry of the powder was maintained in the film during the deposition as confirmed by Rutherford backscattering spectroscopy.