XANES, EXAFS and photoluminescence investigations on the amorphous Eu:HfO2.
We report detailed investigations on the local electronic/atomic structure and photoluminescence properties of chemically synthesized Eu:HfO2powders. X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) and photoluminescence (PL) measurements were performed to analyze the crystal structure, local atomic/electronic structure and luminescence properties of the samples. No crystalline phases were detected with Cu Kα (λ=1.5418Å) based XRD; however, local monoclinic structure was confirmed by the Hf L-edge XANES and EXAFS. O K-edge XANES spectral features could be deconvoluted with doublets and triplets in egand t2gorbitals, respectively, which ascribed to the local monoclinic structure for all of the samples. Eu M5,4-edge XANES confirmed the pre-dominancy of Eu3+ions in the HfO2samples with a fractional amount of Eu2+ions. PL spectra revealed the electric dipole allowed (5D0-7F0,2,4) emission properties of Eu:HfO2samples. The orange-red emission is ascribed to the Eu interstitial/surface segregation induced defects.
Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792, South Korea.
Aditya
A
Sharma
Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792, South Korea.
Mayora
M
Varshney
Pohang Accelerator Laboratory, POSTECH, Pohang 37673, South Korea. Electronic address: shj001@postech.ac.kr.
Hyun-Joon
HJ
Shin
Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792, South Korea. Electronic address: khchae@kist.re.kr.
KeunHwa
K
Chae
Advanced Analysis Centre, Korea Institute of Science and Technology, Seoul 02792, South Korea. Electronic address: sowon@kist.re.kr.
Sung Ok
SO
Won
EXAFS; HfO(2); Photoluminescence; XANES; XRD