Structural and Optical Properties of Phase-Pure UO2, α-U3O8, and α-UO3 Epitaxial Thin Films Grown by Pulsed Laser Deposition
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- West Virginia Univ., Morgantown, WV (United States)
- Univ. of Houston, TX (United States)
- Washington State Univ., Pullman, WA (United States)
- Univ. at Buffalo, NY (United States)
Fundamental understanding of the electronic, chemical, and structural properties of uranium oxides requires the synthesis of high-crystalline-quality epitaxial films of different polymorphs of one material or different phases with various oxygen valence states. Here we report the growth of single-phase epitaxial UO2, α-U3O8, and α-UO3 thin films using pulsed laser deposition. Both oxygen partial pressure and substrate temperature play critical roles in determining the crystal structure of the uranium oxide films. X-ray diffraction and Raman spectroscopy demonstrate that the films are single phase with excellent crystallinity and epitaxially grown on a variety of substrates. Chemical valance states and optical properties of epitaxial uranium oxide films are studied by X-ray photoelectron spectroscopy and UV–vis spectroscopy, which further confirm the high-quality stoichiometric phase-pure uranium oxide thin films. Epitaxial UO2 films show a direct band gap of 2.61 eV, while epitaxial α-UO2, α-U3O8 and α-UO3 films exhibit indirect band gaps of 1.89 and 2.26 eV, respectively. The ability to grow high-quality epitaxy actinide oxide thin films and to access their different phases and polymorphous will have significant benefits to the future applications in nuclear science and technology.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Biological and Environmental Research (BER)
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1726212
- Report Number(s):
- LA-UR-20-24149
- Journal Information:
- ACS Applied Materials and Interfaces, Vol. 12, Issue 31; ISSN 1944-8244
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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