Abstract

The advent of two-dimensional (2D) materials has both transformed the fundamental understanding of processes and properties in condensed matter and accelerated the development of new technologies to tackle societal challenges related to sustainability and energy, information processing, and human health. However, many challenges linger before the unique promise of 2D materials can be fully exploited. This dissertation focuses on understanding the conditions of high-quality 2D material processing and the effect of defects on the properties of 2D materials. This work aims to adapt defect engineering processes that will enable a more precise control of the behavior of 2D materials for scalable implementation in devices. First, methods of isolating high-quality single-crystal monolayers of 2D materials with suitable dimensions for device applications are considered. More specifically, metal-assisted exfoliation is used to isolate large monolayers of molybdenum disulfide (MoS2). The frequency of monolayers obtained, their size and their quality, are assessed for different types of metal-assisted exfoliations. The role of strain and binding energy between each metal and MoS2 on the exfoliation results is presented. Next, the effects of defects on the properties of 2D materials are evaluated, with a focus on hexagonal boron nitride (h-BN) and MoS2. Non-deterministic defects obtained by heat treatment are considered for h-BN. The lattice distortions resulting from the presence of defects are evaluated. Electrical and optical properties changes obtained through defect creation are assessed. Some approaches for more deterministic defect placement and their study with nanoscale precision are presented. The results obtained using a focused electron beam and using nanoscale tip-matter interactions are described. A summary of the work with perspectives on the future developments in fundamental science and in device applications are provided to conclude the body of work.

Notes

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Graduation Date

2023

Semester

Summer

Advisor

Tetard, Laurene

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Physics

Degree Program

Physics

Identifier

CFE0009885

Language

English

Release Date

February 2025

Length of Campus-only Access

1 year

Access Status

Doctoral Dissertation (Campus-only Access)

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Restricted to the UCF community until February 2025; it will then be open access.

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