Observation of Violet-Light Emission Band for Thulium-Doped Tantalum-Oxide Films Produced by Co-Sputtering

Kenta Miura^*, Tetsuhito Suzuki, Osamu Hanaizumi

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

DOI: 10.4236/msa.2015.67067                

Abstract

We prepared thulium-doped tantalum (V) oxide (Ta₂O₅:Tm) thin films using co-sputtering of two Tm₂O₃ pellets and a Ta₂O₅ disc, and we observed photoluminescence (PL) peaks not only around a wavelength of 800 nm due to the ³H₄→³H₆ transition of Tm³⁺ but also around a wavelength of 400 nm (violet) from the films after annealing for the first time. Comparatively narrow PL peaks around the wavelength of 400 nm were observed from the films annealed at 800°C and 900°C for 20 min. The peak intensity from the film annealed at 900°C was approximately four-times stronger than that from the film annealed at 800°C. The origin of the 400-nm peaks seems to be the same as our non-doped Ta₂O₅ thin films deposited using radio-frequency sputtering because we observe PL peaks around 400 - 430 nm from the Ta₂O₅ films. Such a Ta₂O₅:Tm co-sputtered thin film seems to be used as a multi-functional coating film having both anti-reflection and down-conversion effects for realizing a high-efficiency silicon solar cell.

Keywords

Tantalum Oxide, Thulium, Co-Sputtering, Violet-Light Emission Band

Conflicts of Interest

The authors declare no conflicts of interest.

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