AVS 61st International Symposium & Exhibition
    Actinides and Rare Earths Focus Topic Monday Sessions
       Session AC+AS+MI+SA+SS-MoM

Paper AC+AS+MI+SA+SS-MoM11
Cathodoluminescence and Band Gap Studies of Single Crystal UxTh1-xO2 (x = 0.00, 0.01, 0.22)

Monday, November 10, 2014, 11:40 am, Room 301

Session: Spectroscopy, Microscopy and Dichroism of Actinides and Rare Earths
Presenter: David Turner, Oak Ridge Institute for Science and Education
Authors: D. Turner, Oak Ridge Institute for Science and Education
J. Reding, Air Force Institute of Technology
R. Hengehold, Air Force Institute of Technology
T. Kelly, Air Force Institute of Technology
J.M. Mann, Air Force Research Laboratory
J. Kolis, Clemson University
J. Petrosky, Air Force Institute of Technology
Correspondent: Click to Email
Analyses of depth- and temperature-resolved cathodoluminescence experimental techniques have identified many previously unobserved spectral characteristics in UxTh1-xO2 compounds grown using a slow growth hydrothermal method. Three UxTh1-xO2 (x = 0.00, 0.01, 0.22) hydrothermally grown, single crystals were examined using cathodoluminescence. Unique luminescence features were identified as a function of uranium concentration. In the undoped and x = 0.01 UxTh1-xO2, an electronic phase transition is observed as a 20 nm (0.21 eV) red-shift in the wavelength of maximum emission. This red-shift appears when the crystals are heated during both 5 and 10 keV electron beam irradiation. Conversely, a similar phase transition is not observed in the UxTh1-xO2 alloy (x = 0.22). Instead, the wavelength of maximum emission remains constant at 305 nm (4.07 eV). Ultimately, the addition of uranium to the ThO2 lattice increases the band gap of the material which is identified as a 10 nm (0.13 eV) blue shift if the luminescence. Finally, a quadrupole transition is observed in the uranium-containing crystals (O 2p to U 5f) at approximately 600 nm (2.07 eV).