AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of...AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.展开更多
Solid electrolytes for all solid sodium-ion batteries have been attracting much attention as an alternative energy storage system, which have the advantage of being extremely safe because it can be charged quickly and...Solid electrolytes for all solid sodium-ion batteries have been attracting much attention as an alternative energy storage system, which have the advantage of being extremely safe because it can be charged quickly and is nonflammable. We have synthesized anti-perovskite type Na<sub>3</sub>OX (X = Br, and I) electrolytes with high purity, by reactions of halogen mixtures with sodium oxides. After mixing, it was filled in an alumina crucible and heated for 6 hours at 330°C. It was confirmed that a large crystal strain was introduced by eutectication, which might reduce the activation energy of Na ion conduction and lead to an improvement of the conductivity. A relatively higher ionic conductivity of σ = 1.55 × 10<sup>-7</sup> S/cm at 60°C has been obtained for Na<sub>3</sub>OBr<sub>0.6</sub>I<sub>0.4</sub>, which is about three orders higher than that in literature. A different ratio of X (X = Br, I) ions was added into sodium oxide to make the Na<sub>3</sub>OX crystal. The influence of strain introduction on optimizing the bottleneck and improving the conductivity was discussed.展开更多
The excitation process of rare-earth ions in oxide semiconductors for optical emission is thought to be related to defect levels within the band-gap of the host material. In order to improve understanding of the role ...The excitation process of rare-earth ions in oxide semiconductors for optical emission is thought to be related to defect levels within the band-gap of the host material. In order to improve understanding of the role defect levels play in the energy transfer process, junction spectroscopy techniques can be used to investigate the electrically active emission centres. It has been reported that TiO<sub>2</sub> is sensitive to humidity at low temperatures, such as those employed when conducting junction spectroscopy measurements. However, there are not many discussions how to prevent this effect and to improve the quality of measurements. After optimization of samples such as fabrication of flat surface and encupsulant for preventing external effect, temperature dependent-capacitance measurements (C-T) were carried out to characterise shallow traps formed within TiO<sub>2</sub> band-gap. TiO<sub>2</sub> and Sm-doped TiO<sub>2</sub> thin films were deposited on SrTiO<sub>3</sub> (100) templates by laser ablaton and rectifying Ruthenium Oxide Schottky diodes deposited on the TiO<sub>2</sub> surface by laser ablation. A Sm or Sm-related shallow trap was observed in the Arrhenius plot of TiO<sub>2</sub>:Sm. In this paper, we show the optimized sample fabrication/preparation process that stabilizes the junction spectroscopy measurements, even in the presence of humidity and we present initial results obtained on samples using these optimized processing techniques.展开更多
文摘AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.
文摘Solid electrolytes for all solid sodium-ion batteries have been attracting much attention as an alternative energy storage system, which have the advantage of being extremely safe because it can be charged quickly and is nonflammable. We have synthesized anti-perovskite type Na<sub>3</sub>OX (X = Br, and I) electrolytes with high purity, by reactions of halogen mixtures with sodium oxides. After mixing, it was filled in an alumina crucible and heated for 6 hours at 330°C. It was confirmed that a large crystal strain was introduced by eutectication, which might reduce the activation energy of Na ion conduction and lead to an improvement of the conductivity. A relatively higher ionic conductivity of σ = 1.55 × 10<sup>-7</sup> S/cm at 60°C has been obtained for Na<sub>3</sub>OBr<sub>0.6</sub>I<sub>0.4</sub>, which is about three orders higher than that in literature. A different ratio of X (X = Br, I) ions was added into sodium oxide to make the Na<sub>3</sub>OX crystal. The influence of strain introduction on optimizing the bottleneck and improving the conductivity was discussed.
文摘The excitation process of rare-earth ions in oxide semiconductors for optical emission is thought to be related to defect levels within the band-gap of the host material. In order to improve understanding of the role defect levels play in the energy transfer process, junction spectroscopy techniques can be used to investigate the electrically active emission centres. It has been reported that TiO<sub>2</sub> is sensitive to humidity at low temperatures, such as those employed when conducting junction spectroscopy measurements. However, there are not many discussions how to prevent this effect and to improve the quality of measurements. After optimization of samples such as fabrication of flat surface and encupsulant for preventing external effect, temperature dependent-capacitance measurements (C-T) were carried out to characterise shallow traps formed within TiO<sub>2</sub> band-gap. TiO<sub>2</sub> and Sm-doped TiO<sub>2</sub> thin films were deposited on SrTiO<sub>3</sub> (100) templates by laser ablaton and rectifying Ruthenium Oxide Schottky diodes deposited on the TiO<sub>2</sub> surface by laser ablation. A Sm or Sm-related shallow trap was observed in the Arrhenius plot of TiO<sub>2</sub>:Sm. In this paper, we show the optimized sample fabrication/preparation process that stabilizes the junction spectroscopy measurements, even in the presence of humidity and we present initial results obtained on samples using these optimized processing techniques.
