RETRACTED ARTICLE: Effect of target to substrate distance on the material properties of the Y₂SiO₅:Ce³⁺ thin film by pulsed laser deposition

Abstract

The effect of the target–substrate distance on the structural, morphological and photoluminescence (PL) properties of the thin film of the Y₂SiO₅:Ce³⁺ commercial phosphor studied by the pulsed laser deposition method. The distance between the target and the substrate was in the order of 4.0–6.0 cm with a variation of 0.5. X-ray powder diffraction analysis (XRD) shows that the average crystal size is about 37 nm. As the substrate distance is increased, a substantial reduction in film thickness observed from the measurement of mass before and after deposition. This attributes to the semicircular diffusion of the plasma plume due to the reduction of particle species flow over the deposition area of the substrate. The main PL emission peak was observed at 438 nm, which is attributed to the 5d → 4f transition in Ce³⁺ orbitals. The 5d orbital is the first excited state in Ce³⁺ ion energy levels with two close states of ²D_3/2 and ²D_5/2. The splitting of 5d into suborbital ²D_3/2 and ²D_5/2 is due to the electron transition between orbitals of the trivalent cerium ion and the host material. This is studied using three excitation wavelengths (276, 303 and 356 nm) in which all their corresponding emission is in the same region peaked at 438 nm. The highest emission occurs with an excitation wavelength of 356 nm for all substrate distances. The CIE gives the blue emission band for the emission wavelength of 438 nm. The maximum ultraviolet–visible spectrum absorbance was observed at around 356 nm. The scanning electron microscope images show that the sizes and the morphology change as the substrate distance changes. The energy-dispersive X-ray spectrometer shows the presence of all the elements of the compound matrix (Y, Si, O and Ce).