Date of Award

January 2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics & Astrophysics

First Advisor

Nuri Oncel

Abstract

A number of transition metal chalcogenides have displayed promising electrical and magnetic properties that may prove to be ideal materials for various electro-chemical applications. However, production of various transition metal chalcogenides has remains unique to each material and typically these synthesis techniques are not scalable for industrial utilization. Using a generalized heat treatment, various chromium selenium compounds were synthesized. Phase control has been demonstrated by restricting the amount of oxygen present in the reaction vessel. Obtaining different phases as a result of changing an environmental condition suggests a tunable reaction method that can be used to synthesize a number of unique compounds while only changing one parameter. The presence of oxygen drives the composition of chromium to the preferred state, thus effecting the composition of selenium required to create a thermodynamically preferred compound. Since some phases create quasi-two-dimensional materials, a mechanism for controlling phase formation assists in the development and fabrication of devices. Each compound of chromium selenide has a unique crystalline structure, meaning the ability to control the phase formation in effect controls the physical structures itself. Phases of Cr3Se4 and Cr2Se3 were successfully synthesized and subsequently analyzed with X-ray Diffraction and X-ray Photoelectron Spectroscopy methods. While some phases are antiferromagnetic, other phases have thermoelectric properties. Other phases may prove useful in electrode architecture applications due to the multilayer crystal structure.

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