Structural, surface and luminescent properties of SrF2:Eu annealed thin films

• Published in: Vacuum 2021-09, Vol.191, p.110362, Article 110362
• Main Authors: Yagoub, M.Y.A., Swart, H.C., Coetsee, E.
• Format: Article
• Language: English
• Subjects: 5D0-7F0 transition; Annealing effect; Eu2+ emission; SrF2 thin film; XPS depth Profile
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2021.110362

The effect of calcined temperature on the structural, surface and luminescent properties of a SrF2:Eu thin film were investigated for possible application as a downshifting layer for solar cell application. The film was deposited on sodium lime glass by a spin coating method and obtained after heat-treatment under Ar/H2 atmosphere. The thin film's structure as well as the morphology were investigated with X-ray diffraction and scanning electron microscopy, respectively. The elemental composition of the film was obtained with X-ray photoelectron spectroscopy (XPS). The XPS depth profile showed that oxygen and silicon segregated into the 600 °C calcined film and formed an intermediate layer. The XPS results for the SrF2 thin films confirmed that the elements of thin film existed in their stable form on the surface. The electric dipole allowed transitions of Eu2+ ions dominated the film's photoluminescent (PL) spectra at low calcination temperatures. The 5D0-7F0 PL transition of Eu3+ was, however, observed at elevated temperatures. The results suggested that Eu might be a good sensitizer for other lanthanide ions, such as Tb3+ and Er3+, at low temperature treatments. •Temperature treatment affects the SrF2:Eu-glass substrate thin film interface.•Impurities in the SrF2 thin film alter the transparency of the thin film.•The thin film's thickness enhanced the emission property of Eu3+ ion.