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Published September 29, 2020 | Published + Supplemental Material
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Aluminum Oxide Nanoparticle Films Deposited from a Nonthermal Plasma: Synthesis, Characterization, and Crystallization


Aluminum oxide, both in amorphous and crystalline forms, is a widely used inorganic ceramic material because of its chemical and structural properties. In this work, we synthesized amorphous aluminum oxide nanoparticles using a capacitively coupled nonthermal plasma utilizing trimethylaluminum and oxygen as precursors and studied their crystallization and phase transformation behavior through postsynthetic annealing. The use of two reactor geometries resulted in amorphous aluminum oxide nanoparticles with similar compositions but different sizes. Size tuning of these nanoparticles was achieved by varying the reactor pressure to produce amorphous aluminum oxide nanoparticles ranging from 6 to 22 nm. During postsynthetic annealing, powder samples of amorphous nanoparticles began to crystallize at 800 °C, forming crystalline θ and γ phase alumina. Their phase transformation behavior was found to be size-dependent in that powders of small 6 nm amorphous particles transformed to form phase-pure α-Al₂O₃ at 1100 °C, while powders of large 11 nm particles remained in the θ and γ phases. This phenomenon is attributed to the fast rate of densification and neck formation in small amorphous aluminum oxide particles.

Additional Information

© 2020 American Chemical Society. This is an open access article published under a Creative Commons Non-Commercial No Derivative Works (CC-BY-NC-ND) Attribution License, which permits copying and redistribution of the article, and creation of adaptations, all for non-commercial purposes. Received: July 13, 2020; Accepted: August 31, 2020; Published: September 14, 2020. This work is supported by the Army Research Office under MURI project under W911NF-18-1-0240. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the National Science Foundation through the MRSEC program grant DMR-1420013. The authors declare no competing financial interest.

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Published - acsomega.0c03353.pdf

Supplemental Material - ao0c03353_si_001.pdf


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