TITLE:
Photoluminescence Properties of Thulium and Cerium Co-Doped Tantalum-Oxide Films Prepared by Radio-Frequency Co-Sputtering
AUTHORS:
Kenta Miura, Takumi Osawa, Yuya Yokota, Tetsuhito Suzuki, Osamu Hanaizumi
KEYWORDS:
Tantalum Oxide, Thulium, Cerium, Co-Sputtering, Photoluminescence
JOURNAL NAME:
Materials Sciences and Applications,
Vol.6 No.4,
March
26,
2015
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.