Date of Award
Master of Science
Thang Ba Hoang
The sulfurization of MoO3 using Chemical Vapor Deposition is a common technique to synthesize MoS2 nanomaterials such as horizontal mono- and few layer nanosheets. Vertically aligned nanosheets can also be deposited under certain conditions using this method. To our knowledge, however, growth of MoS2 nanosheets with plasma enhanced CVD has not been explored so far. In this study, a remote plasma was introduced into the CVD chamber and the effect of plasma on MoS2 growth was investigated. Sulfur and MoO3 powders were used as the source materials, and the reaction temperature was controlled from 500 to 850 °C. Raman spectroscopy, x-ray diffraction, and scanning electron microscopy were used to characterize the structure and properties of the nanostructures. Introduction of plasma was found to affect the growth mode of MoS2 significantly, depending on the pressure, plasma power, and temperature. The plasma tends to promote the growth of flat nanosheets at lower pressure and high temperature or high pressure and low temperature while it enhances the growth of vertical nanosheets at high pressure and high temperature or low pressure and low temperature. These two growth modes compete with each other and the resultant morphology depends on the growth conditions and plasma power and time to be introduced. This study helps to understand the growth mechanism of MoS2 and opens an opportunity for controlling the material growth and doping by plasma.
dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Chen, Jiyang, "Plasma Assisted Chemical Vapor Deposition of Molybdenum Disulfide Nanosheets" (2017). Electronic Theses and Dissertations. 1705.