The influence of substrate temperature on the structural and luminescent properties of as-deposited SrGa₂S₄:Ce³⁺ thin films coated with a TaSi₂ thin layer

SrGa₂S₄:Ce³⁺ thin films coated with a very thin layer of TaSi₂ were deposited on Si(100) substrates utilizing the pulsed laser deposition system. During the ablation of the targets for thin films preparation, the Si(100) substrate temperature varied in the range of 400-600 C. The as-deposited SrGa₂S₄:Ce³⁺ films showed an orthorhombic crystal structure, and the TaSi₂ coating layer showed a hexagonal structure. The films maintained the crystal structures within the temperature ranges of 400-600 C. The distribution of particles with irregular sizes contributing to a difference in surface roughness of the as-prepared thin films was observed by atomic force microscopy. The films showed a broad photoluminescence (PL) peak at 416 nm, and the maximum PL intensity, as compared to other films, was observed for a film deposited at a substrate temperature of 450 C. Two broad cathodoluminescence peaks (440 and 490 nm) due to Ce³⁺ emission were observed for a film deposited at a substrate temperature of 450 C. The presence of the TaSi₂ coating layer on the SrGa₂S₄:Ce³⁺ thin films was confirmed with Auger electron spectroscopy surface elemental analysis, and Auger depth profiles showed uniform concentrations of the main elements in the deposited films. (orig.)