Selected zinc chalcogenide nanomaterials with novel structure and functionality

Abstract

In this thesis, we aim to venture beyond simple structural forms and study nanomaterials with various levels of structural complexity in the zinc chalcogenide family. For vertically-aligned multi-segment ZnO nanowire arrays, we demonstrate their synthesis through homoepitaxial re-growths. We then implement a scanning electron-beam heating technique to generate spatially-resolved thermal resistance profiles of single two-segment ZnO nanowires. For a single cleaved ZnO nanowire that has been connected through van der Waals interactions, we show that it is possible to achieve nanoscale bistable thermal conduction in such a system by utilizing the single cleaved ZnO nanowire as the active thermal conduction channel and taking advantage of intrinsic thermomechanical characteristics of the test platform. Finally we present our attempts in synthesizing and studying quasi-periodically twinned ZnTe nanoplates. Their possible growth mechanisms are discussed. We then demonstrate via optical measurements that these nanostructures exhibit an enhanced level of electron-phonon coupling.