Photoluminescence Properties of Thulium and Cerium Co-Doped Tantalum-Oxide Films Prepared by Radio-Frequency Co-Sputtering

Kenta Miura^*, Takumi Osawa, Yuya Yokota, Tetsuhito Suzuki, Osamu Hanaizumi

Graduate School of Science and Technology, Gunma University, Kiryu, Japan.

DOI: 10.4236/msa.2015.64031                

Abstract

We prepared thulium and cerium co-doped tantalum-oxide (Ta₂O₅ :Tm, Ce) thin films by radiofrequency co-sputtering of Tm₂O₃ and CeO₂ pellets on a Ta₂O₅ disc for the first time, and photoluminescence (PL) properties of the films annealed at 700°C, 800°C, 900°C, or 1000°C for 20 min were evaluated. PL peaks around a wavelength of 800 nm due to Tm³⁺ were observed for films annealed at 900°C or 1000°C. The peak intensities of films prepared using one Tm₂O₃ pellet and one CeO₂ pellet were much stronger than those of films prepared using one Tm₂O₃ pellet and two CeO₂ pellets or films prepared using two Tm₂O₃ pellets and one CeO₂ pellet. To obtain the strongest PL intensity from the film, the proper Tm concentration was estimated to be around 1.0 mol%, and the proper Ce concentration was estimated to be around 1.3 mol%. Such Ta₂O₅:Tm, Ce co-sputtered thin films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel light-emitting devices, and they will also be used as anti-reflection and downconversion layers for realizing high-efficiency silicon solar cells.

Keywords

Tantalum Oxide, Thulium, Cerium, Co-Sputtering, Photoluminescence

Conflicts of Interest

The authors declare no conflicts of interest.

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