Band-to-band transitions and critical points in the near-infrared to vacuum ultraviolet dielectric functions of single crystal urania and thoria

Authors

Alyssa Mock, University of Nebraska-LincolnFollow
Christina Dugan, Air Force Institute of TechnologyFollow
Sean Knight, University of Nebraska-LincolnFollow
Rafal Korlacki, University of Nebraska at LincolnFollow
J. Matthew Mann, Air Force Research LaboratoryFollow
Martin M. Kimani, Air Force Research LaboratoryFollow
James C. Petrosky, Air Force Institute of TechnologyFollow
Peter A. Dowben, University of Nebraska-LincolnFollow
Mathias Schubert, University of Nebraska-Lincoln & Leibniz Institute of Polymer Research (IPF) DresdenFollow

ORCID IDs

Alyssa Mock

Sean Knight

Peter A. Dowben

Mathias Schubert

Document Type

Article

Date of this Version

2019

Citation

Appl. Phys. Lett. 114, 211901 (2019)

Comments

https://doi.org/10.1063/1.5087059

Abstract

Band-to-band transition energy parameters for single-crystal actinide samples of uranium oxide and thorium oxide were determined and compared using spectroscopic ellipsometry and critical-point dielectric function analyses. Spectroscopic ellipsometry measurements from the near-infrared to the vacuum ultraviolet spectral region were used to determine the dielectric functions of uranium oxide and thorium oxide. The critical-point structure is similar between UO₂ and ThO₂ but strongly blue shifted for ThO₂. We find bandgap energies of 2.1 eV and 5.4 eV for UO₂ and ThO₂, respectively.