Exploration of structure-property relationship and Growth mechanism of 1D nanowires using transmission electron microscopy

Doctoral Candidate Name: Manira Akter
Program: Mechanical Engineering
Defense Date and Time: December 21, 2022 – 10:00 PM
Defense Location: Zoom (https://charlotte-edu.zoom.us/j/97274987319?pwd=ZXl2VjhqL0s3NWVvT2ZLMzhkdnBHdz09)
Committee chair’s Name: Dr. Terry Xu
Committee Members: Dr. Haitao Zhang, Dr. Youxing Chen, Dr. Thomas Schmedake
Abstract:

One dimensional (1D) nanostructured materials are the materials having one external dimension outside the nanoscale range and the other two dimensions in the nanoscale range such as nanowires (NWs). Due to their unique one dimensionality, 1D NWs are considered as the ideal systems to investigate many foundational concepts in physical science and engineering. Along the same line, NWs can be used to establish correlation between their structural parameters, dimensionality, size, and functional properties. Inspired by the vapor-liquid-solid (VLS) growth mechanism provided by R.S. Wagner, NW synthesis started in the early 1990s. In the following three decades, NW research field expanded significantly in terms of synthesis, characterization of structures and properties. However, correlation of the properties with well-understood NW structures and rational synthesis of different NWs with desired properties are two main roadblocks for the wide application of different types of NWs, which are the main focus of this dissertation.
This dissertation consists of two parts. The first part is a collaborative work with researchers from Vanderbilt University and Pennsylvania State University and the goal is to find if any correlation exists between structural parameters, morphology (such as lattice constants and dimensions) and thermal properties of niobium selenide (NbSe3) NWs. NbSe3 is a chain-like structure with molecular chains joined by van der Waals (VdW) force and suitable for the exploration of the effect of electron-phonon (e-ph) interaction on the thermal conductivity. However, superdiffusive thermal transport was observed for ultra-thin NbSe3 NWs (hydraulic diameter