Influence of deposition atmosphere and substrate temperature on the structure, morphology, and photoluminescence of pulsed laser deposited La_0.5Gd_1.5SiO₅:Dy³⁺

Dysprosium doped mixed lanthanum gadolinium oxyorthosilicate (La_0.5Gd_1.5SiO₅:Dy³⁺) thin films were laser ablated on Si (111) substrates. The films were deposited in different atmospheres [vacuum, argon, and oxygen (O₂)] and also at different deposition temperatures (50, 200, 300, 400, and 500 °C) in O₂. The X-ray diffraction patterns preferentially showed two peaks, one from Gd₂SiO₅ and one from La₂SiO₅. The surface topography and particle morphology of the films were studied using atomic force microscopy and field emission scanning electron microscope. The Rutherford backscattering spectroscopy (RBS) spectra and the energy dispersive X-ray spectroscopy spectra confirmed the presence of O, Si, La, Gd, and Dy in the films. The thickness of the films determined from the RBS data were in the micrometer range and changes with the substrate temperature and deposition atmosphere. The electronic states of the films were analyzed using X-ray photoelectron spectroscopy. The photoluminescence (PL) excitation showed a prominent peak around 226 nm from which the emission spectra were measured. The emission spectra showed two prominent peaks at 488 and 578 nm due to f-f electronic transition of Dy³⁺. The highest PL intensity was obtained from the film deposited in O₂ at the substrate temperature of 200 °C.