Nanoscience and Nanotechnology Commons^™

Scanning Probe Microscopy Measurements On 2d Materials And Iridates, Armin Ansary

Theses and Dissertations--Physics and Astronomy

In the past two decades, there has been a quest to understand and utilize novel materials such as iridates and two-dimensional (2D) materials. These classes of materials show a lot of interesting properties both in theoretical predictions as well as experimental results. Physical properties of some of these materials have been investigated using scanning probe measurements, along with other techniques.

One-dimensional (1D) catalytic etching was investigated in few-layer hexagonal boron nitride (hBN) films. Etching of hBN was shown to share several similarities with that of graphitic films. As in graphitic films, etch tracks in hBN commenced at film edges and …

Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse

Legacy Theses & Dissertations (2009 - 2024)

This dissertation presents theoretical and experimental studies in carbon nanotubes (CNTs), graphene, and van der Waals heterostructures. The first half of the dissertation focuses on cutting edge tight-binding-based quantum transport models which are used to study proton irradiation-induced single-event effects in carbon nanotubes [1], total ionizing dose effects in graphene [2], quantum hall effect in graded graphene p-n junctions [3], and ballistic electron focusing in graphene p-n junctions [4]. In each study, tight-binding models are developed, with heavy emphasis on tying to experimental data. Once benchmarked against experiment, properties of each system which are difficult to access in the laboratory, …

Preparation And Characterization Of Van Der Waals Heterostructures, Horacio Coy Diaz

USF Tampa Graduate Theses and Dissertations

In this dissertation different van der Waals heterostructures such as graphene-MoS₂ and MoTe₂-MoS₂ were prepared and characterized. In the first heterostructure, polycrystalline graphene was synthesized by chemical vapor deposition and transferred on top of MoS₂ single crystal. In the second heterostructure, MoTe₂ monolayers were deposited on MoS₂ by molecular beam epitaxy.

Characterization of graphene-MoS₂ heterostructures was conducted by spin and angle resolve spectroscopy which showed that the electronic structure of the bulk MoS₂ and graphene in this van der Waals heterostructures is modified. For MoS₂ underneath the graphene, a band …

Transport And Optical Properties Of Low-Dimensional Complex Systems, Andrii Iurov

Dissertations, Theses, and Capstone Projects

Over the last five years of my research work, I, my research was mainly concerned with certain crucial tunneling, transport and optical properties of novel low-dimensional graphitic and carbon-based materials as well as topological insulators. Both single-electron and many-body problems were addressed. We investigated the Dirac electrons transmission through a potential barrier in the presence of circularly polarized light. An anomalous photon-assisted enhanced transmission is predicted and explained in a comparison with the well-known Klein paradox. It is demonstrated that the perfect transmission for nearly-head-on collision in an infinite graphene is suppressed in gapped dressed states of electrons, which is …

Nanoscale Manipulation Of Pristine And Functionalized Freestanding Graphene Using Scanning Tunneling Microscopy, Matthew Ackerman

Graduate Theses and Dissertations

Over the past ten years the 2D material graphene has attracted an enourmous amount of attention from researchers from across diciplines and all over the world. Many of its outstanding electronic properties are present only when it is not interacting with a substrate but is instead freestanding. In this work I demonstrate that pristine and functionalized freestanding graphene can be imaged using a scanning tunneling microscope (STM) and that imaging a flexible 2D surface is fundamentally different from imaging a bulk material due to the attraction between the STM tip and the sample. This attraction can be used to manipulate …

Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock

Graduate Theses and Dissertations

Graphene, what some are terming the "new silicon", has the possibility of revolutionizing technology through nanoscale design processes. Fabrication of graphene for device processing is limited largely by the temperatures used in conventional deposition. High temperatures are detrimental to device design where many different materials may be present. For this reason, graphene synthesis at low temperatures using plasma-enhanced chemical vapor deposition is the subject of much research. In this thesis, a tool for ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV-PECVD) and accompanying subsystems, such as control systems and alarms, are designed and implemented to be used in future graphene growths. …

The Influence Of Copper Substrate Orientation On Graphene Growth, Zachary Robert Robinson

Legacy Theses & Dissertations (2009 - 2024)

This dissertation is focused on determining the influence of the copper substrate on graphene grown by \ac{CVD}. Graphene, which can be grown in single atomic layers on copper substrates, has potential applications in future electronic devices. One of the key issues for the use of graphene grown by chemical vapor deposition for device applications is the influence of defects on the transport properties of the graphene. For instance, growth on metal foil substrates results in multi-domain graphene growth because the foil substrates themselves have a variety of different surface terminations. Therefore, they don't serve as a very good template for …