Condensed Matter Physics Commons^™

Nanoscale Thermal And Electronic Properties Of Thin Films Of Graphene And Organic Polyradicals, Sabastine Chukwuemeka Ezugwu

Electronic Thesis and Dissertation Repository

Ultrathin film materials have attracted significant attention in light of their potential applications in very large scale integrated electronics and data storage. For instance, the amount of data that can be addressed and stored in a memory device scales inversely with the thinness of the active layer of these components. In our thesis, we have developed a suite of scanning-probe and nano-optical techniques focused on understanding the electronic surface properties and the thermal conductivity of ultrathin materials. We discuss a few specific examples in which we applied these techniques towards improved performance of thin films of graphene and organic polyradicals …

Self-Assembled Copper Nanoparticle Superlattices On Graphene Thin Films, Tianhao Ouyang

Electronic Thesis and Dissertation Repository

Recently, Giovannetti et al. successfully demonstrated that some metals (such as Cu and Au) only have weak van der waals interaction with graphene and thus can only form weak bonding without severely shifting graphene’s band structure, which describes the energies range of the electrons in the material. Therefore, this opens up windows for graphene enhancement without greatly changing its properties. Furthermore, Zhou et al. later suggested the possibility of self-assembling periodic arrays of alkali atoms on graphene. In our group, graphene thin films fabricated in a cost effective way using solution-processed methods have been used extensively, including decorating …

Omcvd Gold Nanoparticles Covalently Attached To Polystyrene For Biosensing Applications, Sivayini Kandeepan

Electronic Thesis and Dissertation Repository

Remarkable developments and successes were witnessed in the fabrication and implementation of optical sensors based on localized surface plasmon resonance (LSPR) for the investigation of chemical and biological material quantities and to detect lethal diseases such as cancer in early stages. Gold nanoparticles (AuNPs) are ideal candidate for sensing purposes due to their chemical stability, ease of surface functionalization and strong LSPR in the visible range. Although there are several designs of sensors published, most of them are still limited to small scale research laboratory use partly due to their high cost of fabrication and waste management, in particular critical …

Dynamics Of Discs In A Nematic Liquid Crystal, Alena Antipova

Electronic Thesis and Dissertation Repository

In this thesis, a new way of simulating a two-way coupling between a liquid crystal and an immersed object is proposed. It can be used for objects of various geometries and can be expanded to be used for an object of any geometry. Additionally, a simple yet effective model was suggested for calculations of transmitted light through a nematic liquid crystal sample. This model allowed us to clarify the behavior of a ferromagnetic disc in a nematic liquid crystal observed in experiments and incorrectly interpreted at that time.

Our simulations have demonstrated the following: in the absence of external forces …

Simulation Of Heterogeneous Colloidal Particles Immersed In Liquid Crystals, Setarehalsadat Changizrezaei

Electronic Thesis and Dissertation Repository

This thesis describes an investigation of interactions between colloidal particles immersed in a liquid crystal. The presence of colloidal particles in the liquid crystal distorts the director field distorted from its uniform orientation. These elastic distortions produce topological defects around the particles, which induce anisotropic interactions between them, and these anisotropic interactions can be used to manufacture non-closed packed colloidal crystals, such as diamond lattices, which are interesting in photonic applications. First, different types of liquid crystals, the mathematical tools to describe the anisotropic nature of liquid crystals, the Landau-de Gennes free-energy model to investigate the particle’s interaction, and different …

Universal Scaling Properties After Quantum Quenches, Damian Andres Galante

Electronic Thesis and Dissertation Repository

In this Thesis, the problem of a quantum quench in quantum field theories is analyzed. This involves studying the real time evolution of observables in a theory that undergoes a change in one of its couplings. These quenches are then characterized by two parameters: $\delta \lambda$, the magnitude of the quench and most importantly, $\delta t$, the quench duration. In contrast to previous studies of abrupt quenches in the condensed matter theory community, we will be interested in smooth quenches with a finite $\delta t$.

Motivated by existing results in holographic theories, we studied the problem of a fast smooth …

The Study Of Nano-Optics In Hybrid Systems, Marek J. Brzozowski

Electronic Thesis and Dissertation Repository

In this thesis, we study the quantum light-matter interaction in polaritonic heterostructures. These systems are made by combining various nanocomponents, such as quantum dots, graphene films, metallic nanoparticles and metamaterials. These heterostructures are used to develop new optoelectronic devices due to the interaction between nanocomposites.

Photoluminescence quenching and absorption spectrum are determined and an explanatory theory is developed for these polaritonic heterostructures. Photoluminescence quenching is evaluated for a graphene, metallic nanoparticle and quantum dot system. It is shown that average distance between nanocomposites or concentration of nanocomposites affect the output these system produced. Photoluminescence quenching was also evaluated for a …