Fabrication of Tm-doped Ta2O5 thin films using a co-sputtering method

Thulium-doped tantalum-oxide (Ta2O5:Tm) thin films were prepared using a simple co-sputtering method. A remarkable photoluminescence peak having a wavelength of around 800 nm due to Tm3+ was observed from a film annealed at 900 °C for 20 min. The δ-Ta2O5 (hexagonal) phase of the Ta2O5:Tm sputtered film is very important for obtaining strong photoluminescence

Yellow light emission from Ta2O5:Er, Eu, Ce thin films deposited using a simple co-sputtering method

Erbium, europium, and cerium co-doped tantalum oxide (Ta2O5:Er, Eu, Ce) thin films were prepared using a simple co-sputtering method, and yellow light emission was observed by the naked eye from a sample annealed at 900 °C for 20 min. The hexagonal Ta2O5 phase is very important, but the hexagonal CeTa7O19 phase should be avoided to obtain strong yellow light emission from Ta2O5:Er, Eu, Ce films. The co-sputtered films can be used as high-refractive-index and yellow-light-emitting materials of autocloned photonic crystals that can be applied to novel light-emission devices, and they will also be used as anti-reflection and down-conversion layers toward high-efficiency silicon solar cells

Fabrication and evaluation of green-light emitting Ta2O5:Er, Ce co-sputtered thin films

Erbium and cerium co-doped tantalum-oxide (Ta2O5:Er, Ce) thin films were fabricated using radio-frequency co-sputtering of Ta2O5, Er2O3, and CeO2 for the first time. Enhanced green-light emission due to Er3+ that seems to be sensitized by Ce3+ was observed from the film annealed at 900 °C for 20 min. From XRD measurements of the films, the β-Ta2O5 (orthorhombic), δ-Ta2O5 (hexagonal), and (201) Ta2O5 phases seem to be very important for obtaining green PL from them. Such Ta2O5:Er, Ce co-sputtered films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel green-light-emitting devices, and they will also be used as multi-functional coating films that can work both as anti-reflection and down-conversion films for realizing high-efficiency silicon solar cells

Fluorescent Defect Formation in Single Crystalline Diamond by Focused Proton Irradiation

Creation of fluorescent defects at desired position and structures will play an important role for development of quantum devices. Compared to other microfabrication techniques, focused particle beam is excellent tool for defect engineering on wide band-gap semiconductors. There are several studies on micro-processing using various focused particle beam writing (PBW) techniques and some among them successfully demonstrated fabrication of graphite structures in diamond. Recently, we succeeded to control the depth of the micrometer-scaled processed layer by changing energy of the focused ions.These techniques would be applicable to form defects of fluorescent centers in diamond by precise control of PBW microprobe.23rd International Workshop on Inelastic Ion-Surface Collisions (IISC-23

In-air micro-particle-induced X-ray emission imaging and spectroscopy of air-borne particles collected hourly from an automated sampling unit of the atmospheric environmental regional observation system

Particulate matter (PM) collected hourly by an automated sampling unit of the Atmospheric Environmental Regional Observation System (AEROS) was characterized by external micro-particle-induced X-ray emission (PIXE) analysis and imaging. Micro-PIXE analysis revealed the overall elemental composition and differences in the elemental composition ratios of PM2.5 and PM2.5-10 collected as individual spots on Teflon tape filters from the unit, and the blank Teflon tape showed a clean background. Moreover, micro-PIXE imaging visualized regions with different elemental compositions in PM2.5 and PM2.5-10. Accumulation of PM2.5 particles was found frequently on tape filters which accounted approximately for 70% of particular elemental composition including heavy metals like iron, compared to that from whole area. The results suggest that PIXE effectively reveals elemental composition of hourly-collected PM by AEROS system for futuristic application for source apportionment of those over Japan

Investigation of electrically-active deep levels in single-crystalline diamond by particle-induced charge transient spectroscopy

To investigate electrically-active deep levels in high-resistivity single-crystalline diamond, particleinduced charge transient spectroscopy (QTS) techniques were performed using 5.5 MeV alpha particles and 9 MeV carbon focused microprobes. For unintentionally-doped (UID) chemical vapor deposition(CVD) diamond, deep levels with activation energies of 0.35 eV and 0.43 eV were detected which correspond to the activation energy of boron acceptors in diamond. The results suggested that alpha particle and heavy ion induced QTS techniques are the promising candidate for in-situ investigation of deep levelsin high-resistivity semiconductors