Search results for "luminescence."
showing 10 items of 1568 documents
Temperature dependence of luminescence of LiF crystals doped with different metal oxides
2020
Photoluminescence and cathodoluminescence of LiF crystals doped with different binary metal oxides were measured in the wide temperature range of 50-300 K and time interval of 10−8−10−1 s after the nanosecond electron excitation pulse. Both as-grown those and crystals irradiated by an electron beam in range of absorbed dose up to 103 Gy were studied. It is shown that spectral-kinetic characteristics of the luminescence depend on the absorbed dose (type of created/accumulated color centers), the irradiation temperature, the concentration of hydroxyl, which promotes incorporation of the MeO complex (Me: W, Ti, Fe, Li) into the crystal lattice, and the cation-dopants.
Low-temperature luminescence of ScF3 single crystals under excitation by VUV synchrotron radiation
2020
The work was supported by the Latvian Science Council grant LZP-2018/2-0358. The research leading to this result has also been supported by the project CALIPSO plus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. The author is grateful to K. Chernenko (MAX IV Laboratory, Lund University) for his assistance during beamtime experiments and to A. I. Popov for the fruitful discussions. V.P. also acknowledges Valsts pētījumu programma “Augstas enerģijas fizika un paātrinātāju tehnoloģijas” (Projekta Nr. VPP-IZM-CERN-2020/1-0002). REFERENCES
Rhodamine (B) photocatalysis under solar light on high crystalline ZnO films grown by home-made DC sputtering
2018
Abstract ZnO thin films were deposited by home-made DC sputtering of zinc target under mixed gases (Argon, Oxygen) plasma on glass substrates. Films were deposited by varying oxygen partial pressure (PO2) from 0.09 to 1.3 mbar in the deposition chamber, at a fixed substrate temperature of 100 °C. The samples were characterized by photoluminescence (PL), X-ray diffraction (XRD), optical transmissions (UV–vis), scanning electron microscopy (SEM) and electrical (Hall effect) measurements. The results indicate that by varying the oxygen pressure in the deposition chamber, the films show a precise and well defined photoluminescence emissions for each range of pressure covering almost the entire …
X-Ray studies on optical and structural properties of ZnO nanostructured thin films
2006
Abstract X-ray absorption near-edge fine structure (XANES) studies have been carried out on nanostructured ZnO thin films prepared by atmospheric pressure chemical vapour deposition (APCVD). Films have been characterized by X-ray diffraction (XRD) and optical luminescence spectroscopy exciting with laser light (PL) or X-ray (XEOL). According to XRD measurements, all the APCVD samples reveal a highly (002) oriented crystalline structure. The samples have different thickness (less than 1 μm) and show significant shifts of the PL and XEOL bands in the visible region. Zn K-edge XANES spectra were recorded using synchrotron radiation at BM08 of ESRF (France), by detecting photoluminescence yield…
Low-temperature luminescence of catangasite single crystals under excitation by vacuum ultraviolet synchrotron radiation
2020
The luminescent properties of Ca3TaGa3Si2O14 (CTGS, catangasite) single crystals have been studied by means of the vacuum ultraviolet excitation spectroscopy utilizing synchrotron radiation from 1.5 GeV storage ring of MAX IV synchrotron facility. Two emission bands at 320 nm (3.87 eV) and 445 nm (2.78 eV) have been detected. Examining excitation spectra in vacuum ultraviolet spectral range, the 320 nm emission band was explained as the emission band of self-trapped exciton in CTGS single crystal. Its atomic structure is discussed. It is also proposed that the 445 nm (2.78 eV) emission in the CTGS is due to the F centers, which have shown a well-resolved excitation (absorption) band at 5.1 …
Low-temperature luminescence of CdI2 under synchrotron radiation
2020
Synchrotron radiation is applied to study visible and UV luminescence spectra and their excitation spectra of undoped as well as In and Sb doped cadmium iodide crystals at 10 K. The origin of principal luminescence bands and the role of impurities in the formation of emission centers are discussed. The luminescence properties have been explained based on the electronic structure of CdI2 crystals.
Comparative study of the luminescence properties of macro- and nanocrystalline MgO using synchrotron radiation
2013
MgO nano-powder with an average crystallite size of nanoparticles ranging 10-15 nm was synthesized using the extractive-pyrolytic method and was studied by room temperature VUV spectroscopy under synchrotron radiation excitation. Comparative analysis of their luminescent properties with that of mac- rocrystalline powder analogues and an MgO single crystal, grown by the arc-fusion method, has been per- formed under excitation by pulsed VUV synchrotron radiation. Special attention was paid to VUV spectral range, which is not reachable with commonly used lamp and laser sources. A considerable blue shift of about 0.3 eV in the excitation spectra of 2.95 eV emission band, was revealed in nanocry…
Accumulation of radiation defects and modification of micromechanical properties under MgO crystal irradiation with swift 132Xe ions
2020
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. A.A. also acknowledges support via the project GF AP05134257 of Ministry of Education and Science of the Republic of Kazakhstan .
Shallow and deep trap levels in X-ray irradiated β-Ga2O3: Mg
2019
Abstract The results of the investigation of thermostimulated luminescence (TSL) and photoconductivity (PC) of the X-ray irradiated undoped and Mg2+ doped β-Ga2O3 single crystals are presented. Three low-temperature peaks at 116 K, 147 K and 165 K are observed on the TSL glow curves of undoped crystals. The high-temperature TSL peaks at 354 K and 385 K are dominant in Mg2+ doped crystals. The correlation between doping with Mg2+ ions and the local energy levels of the intrinsic structural defects of β-Ga2O3, which are responsible for the TSL peaks and PC, is established. The nature of TSL peaks and the appropriate photoconductivity excitation bands are discussed.
EPR and optical spectroscopy of neutron-irradiated Gd3Ga5O12 single crystals
2020
Abstract In this paper, we have performed comparative analysis of EPR, optical absorption (OA) and luminescence spectra for a series of Gd3Ga5O12 (GGG) single crystals irradiated with fast neutrons with fluencies varied from 1016 to 1020n/cm2. In a crystal irradiated with the maximum neutron fluence, the EPR spectra demonstrated the formation of several paramagnetic defects. In particular, EPR spectrum shows a strong resonance at (effective) g ≈ 1.4 with practically isotropic behavior in the crystal rotation around the [1 1 1] direction (magnetic field being perpendicular to [1 1 1]) and several weaker lines in the g ≈ 1.1–2.6 region, which show more pronounced angular dependences. While th…