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Metal-Oxide Nanocomposite for Tunable Physical Properties

thesis
posted on 05.08.2020 by Shikhar Misra

Understanding how light interacts with the matter is essential for developing future opto-electronic devices. Furthermore, tuning such light-matter interaction requires designing new material platforms that is essential for developing devices which are functional in different light wavelength regimes. Among these designs, particle-in-matrix, multilayer or nanowire morphology, consisting of metal and dielectric materials, have been demonstrated for achieving improved physical and optical properties, such as ferroelectricity, ferromagnetism and negative refraction. For example, Au-TiO2 two phase nanocomposite has been explored in this dissertation as a way of achieving enhanced photocatalysis. However, due to the availability of a limited range of structures in terms of crystallinity and morphology in the two-phase nanocomposites, a greater design flexibility and structural complexity along with versatile growth techniques are needed for developing next generation integrated photonic and electronic devices. This can be achieved by incorporating a third phase through the three phase nanocomposite designs by judicious selection of materials and functionalities.

In this dissertation, a new nanocomposite design having three different phases has been introduced: Au, BaTiO3 and ZnO, which grow in a highly ordered ‘nanoman’-like structure. More interestingly, the three phases in the novel ‘nanoman’-like structure combine to give an emergent new property which are not found individually in the three phases. The ordered ‘nanoman’-like structures enable a high degree of tunability in their optical and electrical properties, including the hyperbolic dispersion in the visible and near infrared regime, in addition to the prominent ferroelectric/piezoelectric properties. Moreover, the growth kinetics and the thermal stability (using in-situ Transmission Electron Microscopy) of the ‘nanoman’ structures has also been studied. This study introduces a new growth paradigm of fabricating three-phase nanocomposite that will surely generate wide interests with potential applications to different systems. The ordered three-phase ‘nanoman’ structures present enormous opportunities for novel complex nanocomposite designs towards future optical, electrical and magnetic property tuning.

Funding

NSF DMR 1643911

NSF DMR 1809520

History

Degree Type

Doctor of Philosophy

Department

Materials Engineering

Campus location

West Lafayette

Advisor/Supervisor/Committee Chair

Dr. Haiyan Wang

Additional Committee Member 2

Dr. John Blendell

Additional Committee Member 3

Dr. Kenneth H. Sandhage

Additional Committee Member 4

Dr. Zhihong Chen

Licence

Exports