Compositional Tuning of Ultrathin Surface Oxides on Metal and Alloy Substrates Using Photons: Dynamic Simulations and Experiments
Oxide synthesis with controlled functional properties is desirable for a plethora of applications but is elusive due to oxide growth kinetics. Here, we report on the ability to modify the structure and composition of ultra-thin oxides grown on Ni-Al alloy surfaces at room temperature utilizing photon illumination. Atomistic simulations that take into account dynamic charge transfer predict that the electric field produced across an oxide film in photon-assisted synthesis overcomes the activation energy barrier for ionic migration, leading to enhanced oxidation kinetics and oxygen incorporation into the oxide, enabling us to control the oxide composition at atomic length scales. Experiments (near-edge x-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy) indicate that the native oxide on 5%Ni-Al alloy is primarily composed of aluminum oxide with no nickel oxide whereas the photon-assisted oxide comprises of both aluminum oxide and nickel oxide. The ability to tune the composition at the atomic scale of the ultra-thin oxide films leads to excellent passivity as verified from polarization experiments.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 974913
- Report Number(s):
- PNNL-SA-70354; 18895; KP1704020; TRN: US201007%%873
- Journal Information:
- Physical Review. B, Condensed Matter, 81(8):Art. No. 085406, Vol. 81, Issue 8; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
ACTIVATION ENERGY
ALLOYS
ALUMINIUM
ELECTRIC FIELDS
FINE STRUCTURE
FUNCTIONALS
ILLUMINANCE
KINETICS
NICKEL OXIDES
OXIDATION
OXIDES
OXYGEN
PASSIVITY
PHOTONS
POLARIZATION
SUBSTRATES
SYNTHESIS
TUNING
X-RAY PHOTOELECTRON SPECTROSCOPY
Environmental Molecular Sciences Laboratory