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Nanoscale Self-patterning and Engineering of YSZ Surfaces

Niu, Zhiyuan
http://rave.ohiolink.edu/etdc/view?acc_num=osu1461188677

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Materials Science and Engineering.
Strain energy induced self-assembly has recently been discovered in the rare earth oxides (REO)/yttria-stabilized zirconia (YSZ) systems. This dissertation aims to deepen previous mechanistic understanding of this phenomenon and to develop a cost-efficient technique that can be used to pattern a large surface with nanoscale features. In this work, a new REO source dispersion strategy was used to address the dilemma of the process simplicity and the source controllability. With this method, we investigated the growth kinetics of the nanostructures in a quantitative manner. In contrast to previous hypothesis that both the nanoislands and the nanobars have parabolic growth kinetics, we observed a parabolic relation only for the nanobars on YSZ(110). It was further discovered that the growth is anisotropic on YSZ(110), which might explain the formation of bars instead of islands. In efforts to improve the order of the nanoislands, we investigated the surface step morphology and the formation of self-assembled nanoislands on two different types of miscut yttria-stabilized zirconia (YSZ) substrates. It was found that ordered step arrays can be produced on both (001)-[110] and (001)-[100] miscut YSZ substrates via pre-annealing. These steps are subsequently used as templates for the self-assembly of the nanoislands, which results in significantly improved alignment of the islands along the step direction. Additionally, we observed a novel step faceting only on the (001)-[100] miscut YSZ substrates where the original [100]-steps decompose into <110>-segments. Preliminary investigation indicates that this faceting is induced by doping via surface diffusion, while the elastic interaction between the faceted steps also plays a significant role. We further investigated the impact of annealing gas environment - an overlooked factor in previous studies - on the nanostructure morphology. It was found that 5% H2-95% N2 forming gas environment can promote the reactions in Eu2O3/YSZ(001) systems, which results in an improvement in nanostructure coverage. It is believed that the existence of H2 has dynamically changed the nanostructure formation. The role of H2 and its effect on other REO/YSZ systems were also explored and discussed.
Sheikh Akbar (Advisor)
Suliman Dregia (Advisor)
Yunzhi Wang (Committee Member)
155 p.
Engineering; Materials Science
Self-assembly; Surface patterning; YSZ; Nanoislands; Nanobars; Surface steps

Recommended Citations

Citations

  • Niu, Z. (2016). Nanoscale Self-patterning and Engineering of YSZ Surfaces [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461188677

    APA Style (7th edition)

  • Niu, Zhiyuan. Nanoscale Self-patterning and Engineering of YSZ Surfaces. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1461188677.

    MLA Style (8th edition)

  • Niu, Zhiyuan. "Nanoscale Self-patterning and Engineering of YSZ Surfaces." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461188677

    Chicago Manual of Style (17th edition)

osu1461188677
241
© 2016, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.