Novel ZnS Nanostructures: Synthesis, Growth Mechanism, and Applications

Abstract

Motivated by a desire to understand the basic concepts of one-dimensional nanostructure growth, the research described in this thesis aims at understanding the basic mechanisms controlling the synthesis and formation of a specific group of II-VI semiconducting nanostructures. In particular, this thesis examines one-dimensional nanostructures (such as nanobelts and nanowires) and different morphologies of ZnS that result from the interesting properties that the materials have at the nanoscale. In order to understand how to tune these properties in the nanostructure, it is necessary to have an understanding of the growth mechanism that dictates the morphology, structure, and rate of growth of the nanomaterial. It is necessary to understand what impact changes to the macroscopic setup in the experiment have on the nanoscopic scale of the nanomaterials. Having a larger understanding and exerting more precise control over the growth of nanomaterials will allow a higher level of selectivity, more control over dimensionality and the type of morphology, easier manipulation, and the simpler incorporation of these structures into a nanotechnological device. The main focus of the research was on CdSe and ZnS, with the bulk of the research being conducted on ZnS nanostructures. These materials were chosen for their potential for extensive research, their possible applications in optoelectronics, their potential to form the wurtzite crystal structure, and the potential generalization of results to other nanomaterials. The framework for the research is given first. Then a description of the experimental setup and a model for the growth of nanostructures is discussed. A brief overview of the synthesis of CdSe nanostructures is given and then a detailed analysis of the synthesis of specific ZnS one-dimensional morphologies is presented.