0000000000273964
AUTHOR
Marko Huttula
Oxygen influence on luminescence properties of rare-earth doped NaLaF 4
Abstract Luminescence properties of erbium and europium doped NaLaF4 with different oxygen content have been studied. Vacuum ultraviolet (VUV) excitation luminescence spectroscopy technique has been applied by using synchrotron radiation excitation. It was found that oxygen impurity leads to significant degradation of Er3+ or Eu3+ emission under VUV excitation. The intensive O2−–Er3+ charge transfer excitation band has been detected from oxygen abundant NaLaF4 in the 150–165 nm spectral range. This band reveals a competing absorption mechanism in oxygen containing NaLaF4. It is clearly demonstrated that one reason for the Er3+ emission degradation in oxygen abundant NaLaF4 is strong suppres…
Progress in development of a new luminescence setup at the FinEstBeAMS beamline of the MAX IV laboratory
The main funding for the FinEstBeAMS beamline has been obtained from the European Union through the European Regional Development Fund (project “Estonian beamline to MAX-IV synchrotron”, granted to the University of Tartu) and from the Academy of Finland through the Finnish Research Infrastructure funding projects ( FIRI2010 , FIRI2013 , FIRI2014 ). The authors also acknowledge the funding contributions of the University of Oulu , University of Turku , Tampere University of Technology , the Estonian Research Council ( IUT 2-25 , IUT 2-26 , PRG-111 ), as well as the Estonian Centre of Excellence in Research “Advanced materials and high-technology devices for sustainable energetics, sensorics…
X-RAY PHOTOEMISSION ELECTRON MICROSCOPE DETERMINATION OF ORIGINS OF ROOM TEMPERATURE FERROMAGNETISM AND PHOTOLUMINESCENCE IN HIGHCo-CONTENTCoxZn1-xOFILMS
In this paper, we reported on the X-ray photoemission electron microscope (XPEEM) determination of magnetic and luminescence origins for two CoxZn1-xO films. The cobalt fraction x of radio frequency co-sputtered samples were 0.86(2) and 0.92(2), respectively. Films were ferromagnetic and semiconductive. Unique narrow green color lines beside the ZnO intrinsic emissions were found with a decay time in microsecond range at room temperature. Origins of magnetic and luminescence properties were determined with XPEEM. The X-ray absorption near edge structure at the Co L3-edge denoted that Co was partially oxidized, and phase-contrast images together with chemical composition identification furt…
Performance and characterization of the FinEstBeAMS beamline at the MAX IV Laboratory
European Regional Development Fund (grant No. TK-141 HiTechDevices 2014-2020.4.01.15-0011 to University of Tartu; grant No. MAX-TEENUS 2014-2020.4.01.20-0278 to University of Tartu; grant No. Eesti Kiirekanal SLOFY11156T/1 to University of Tartu); Estonian Research Council (grant No. PRG-629 to University of Tartu); Jane & Aatos Erkko Foundation (grant No. SOFUS); Business Finland (grant No. 1464/31/2019); Academy of Finland (grant No. 319042; grant No. 326461; grant No. 326406; grant No. 320165); University of Oulu; University of Turku; Tampere University; University of Tartu.
Luminescence and vacuum ultraviolet excitation spectroscopy of samarium doped SrB4O7
Abstract Sm2+ and Sm3+ co-doped SrB4O7 could be utilized in several high-level optical devices and fundamental knowledge about the optical behavior of these materials benefits the development of luminescent applications. Herein, we report luminescence and its vacuum ultraviolet (VUV) excitation spectra in samarium doped SrB4O7. Both, Sm2+ and Sm3+ luminescence centers have been examined and distinguished in the emission and the excitation spectra investigated under synchrotron radiation. The contribution of either Sm2+ or Sm3+ emission lines into the emission spectra heavily depended on the excitation energy, and strong f-f transitions of both Sm2+ and Sm3+ were detected. At 10 K, a broad i…