TITLE:
Observation of Blue-Light Emission Band from Eu-Doped Ta2O5 Thin Films Prepared Using Co-Sputtering
AUTHORS:
Kenta Miura, Yuki Arai, Osamu Hanaizumi
KEYWORDS:
Ta2O5, Eu, Co-Sputtering, Blue-Light Emission Band
JOURNAL NAME:
Materials Sciences and Applications,
Vol.6 No.7,
July
22,
2015
ABSTRACT: In this paper, we report on the first observation of blue-light emission bands from europium-doped tantalum pentoxide (Ta2O5:Eu) thin films prepared using a simple co-sputtering method. We prepared four specimens from one as-deposited sample, and we subsequently annealed them at 700°C, 800°C, 900°C, or 1000°C for 20 min. Four remarkable photoluminescence (PL) peaks at wavelengths of 600, 620, 650, and 700 nm due to the 5D0→7F1, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transitions of Eu3+ were observed from all the specimens, and blue PL peaks around a wavelength of 450 nm were also observed from the specimens annealed at 800°C, 900°C, and 1000°C. The blue PL peaks seem to be originated from the 4f65d1→4f7 transition of Eu2+. Both Eu3+ and Eu2+ ions seem to exist in our Ta2O5:Eu co-sputtered thin films annealed at temperatures from 800°C to 1000°C. Such Ta2O5:Eu co-sputtered thin films seem to be used as multi-functional coating films having both anti-reflection and down-conversion effects for realizing high-efficiency silicon solar cells.