Radiophotoluminescence properties of Eu-doped Li2SrSiO4 for radiation detectors

Japanese Journal of Applied Physics

Published On 2023/12/20

To search for new radiophotoluminescence (RPL) materials, Eu-doped Li 2 SrSiO 4 was synthesized by the solid-state reaction and then studied its RPL properties for radiation detector applications. All the samples were identified to be Li 2 SrSiO 4 by X-ray diffraction. The as-prepared sample shows photoluminescence (PL) due to Eu 3+ while an additional PL band appears due to a formation of Eu 2+ after X-ray irradiation. This indicates that the Eu-doped Li 2 SrSiO 4 has RPL properties. The sensitivity of RPL (or PL intensity of Eu 2+) to X-ray dose is the highest when the Eu concentration is 0.1%, and the dynamic range is 5–10 000 mGy. In addition, the generated Eu 2+ is so stable that only 5% of the signal degrades over 20 min after irradiation. The RPL signal notably decreases to about 30% of the initial value by heating at 500 C for 100 s, and it is reproducible multiple times even after the heat treatment.

Journal

Japanese Journal of Applied Physics

Published On

2023/12/20

Volume

63

Issue

1

Page

01SP14

Authors

Hidehito Nanto

Hidehito Nanto

Kanazawa Institute of Technology

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H-Index(all)

44

H-Index(since 2020)

19

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

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0

Research Interests

Odor sensor

Dosimeter

Thin films

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Japanese Journal of Applied Physics

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Article Details
Hidehito Nanto

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Kanazawa Institute of Technology

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Article Details
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Article Details
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Japanese Journal of Applied Physics

Competitive coexistence of ferromagnetism and metal–insulatortransition of VO2 nanoparticles

We investigated the magnetic and electric properties of nanometer-sized vanadium dioxide (VO2) particles. VO2 nanoparticles were formed by milling VO2 powder. We measured the magnetic field dependence of the magnetization of the VO2 powder and nanoparticles. The VO2 powder did not exhibit ferromagnetism, whereas the VO2 nanoparticles exhibited ferromagnetism. In addition, we fabricated samples by bridging between electrodes with the VO2 nanoparticles, and the temperature dependence of their resistance was measured. Metal-insulator transitions (MITs) were observed, and the temperature range where the MIT occurred was wider than that in a typical bulk VO2. The VO2 nanoparticles exhibited these properties of ferromagnetism and MIT possibly because of the surface and size effects of the VO2 nanoparticles. These results indicate the first observation of the competitive coexistence of …

Toru Akiyama

Toru Akiyama

Mie University

Japanese Journal of Applied Physics

First-principles study on barrier height of silicon emission from interface into oxide during silicon thermal oxidation

Employing the first-principles calculation, the detailed energy landscape of the path for the Si emission from the interface into the oxide is studied. It is found that the barrier height almost reproduces the experimental values, which indicates that the Si emission surely corresponds to the diffusion of SiO interstitial. It is also found that the barrier height is microscopically rate-limited by the oxygen-vacancy transfer process, which temporarily and inevitably proceeds under a large local tensile strain induced by the diffusion of SiO interstitial.

Atsushi Ogura

Atsushi Ogura

Meiji University

Japanese Journal of Applied Physics

Local thermal conductivity properties of a SiGe nanowire observed by laser power sweep Raman spectroscopy

Using laser power sweep Raman spectroscopy, this research reports that the thermal transport changes with the wire width of silicon-germanium (SiGe) nanowires (NWs). The temperature in SiGe NWs was calculated using the relationship between Raman shift ω and temperature T (dω/dT) to evaluate the correlation between the thermal transport mechanism and SiGe NWs structure. We clarified that the thermal conductivity of the SiGe NWs decreases as the wire width becomes narrower. Also, a positional dependence of the thermal conductivity properties of the SiGe NWs was observed by laser power sweep Raman spectroscopy.

Taeho Kim

Taeho Kim

KAIST

Japanese Journal of Applied Physics

Novel strategies for low-voltage NAND flash memory with negative capacitance effect

Here, we present a novel approach to employing a negative capacitance (NC) phenomenon in the blocking oxide of CTF memory. To achieve this, we developed an inversible mono-domain ferroelectric (IMFE) film through high-pressure post-deposition annealing in a forming gas at 200 atm (FG-HPPDA). The FG-HPPDA process enables to form a uniform alignment of domains and facilitates invertible domain switching behavior in ferroelectrics, generating an internal field by the flexo-electric effect as well as interface-pinned polarization by chemical reaction. Subsequently, to stabilize the NC effect, we fabricated the IMFE/Al2O3 heterostructure, which exhibits an outstanding capacitance-boosting feature. Finally, we successfully demonstrate unprecedented CTF memory with the NC effect in a blocking oxide. Our unique CTF device shows the improved performance (maximum incremental-step-pulse-programming …

Hiroshi Kanai

Hiroshi Kanai

Tohoku University

Japanese Journal of Applied Physics

Automated mode chart generation for finite element analysis of piezoelectric resonators using principal component analysis based on clustering

This paper presents a new clustering method for identifying the vibration mode shapes of piezoelectric resonators using image processing and principal component analysis (PCA). The finite element method (FEM) is an indispensable tool for analyzing the vibration-displacement distribution of resonators and suppressing spurious vibration modes. Although the FEM exports eigenfrequencies as a list, including spurious vibration modes, recognizing the vibration shape of each eigenfrequency requires manual operation by operators to view the displacement distribution and identify the vibration shapes. The proposed method consists of a preprocessing step based on a threshold selection before the PCA step. Preprocessing significantly simplifies the vibration displacement distribution and reduces the amount of data required for post-processing PCA. The mode chart of the AT-cut quartz crystal resonator obtained …