Date of Award

2018

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Physics (PhD)

Administrative Home Department

Department of Physics

Advisor 1

Ravindra Pandey

Committee Member 1

Ranjit Pati

Committee Member 2

Maximilian Seel

Committee Member 3

Loredana Valenzano

Abstract

The interactions of nanomaterial surfaces with biological compounds, e.g. proteins, DNA, etc., unites the biological regime and nanomaterial world. Hybrid systems of boron-nitride nanotubes (BNNTs) and biological compounds are well-suited for a broad range of applications. First-principles methods are used to characterize the interface of these hybrid systems. Previous work has shown that the sensing capabilities of pristine BNNT are limited by long-ranged interactions. In this study the surfaces of pristine and functionalized BNNTs are investigated. The surfaces of the functionalized BNNTs give new properties to the tubes, which may enhance their sensing capabilities, while retaining their stability and chemical inertness. These simulations provide a fundamental understanding of these interaction. During the course of the investigation, two related projects were pursued.

The first tangent characterized a new material that was found during the investigation of defects of BNNTs. The material is a B-N monolayer material (BN2) consisting of a network of extended hexagons. The distinguishable nature of the 2-D material is the presence of bonded N atoms (N-N) in the lattice. Analysis of the phonon dispersion curves suggests this phase of BN2 to be stable. The calculated elastic properties exhibit anisotropic mechanical properties that surpass graphene in the armchair direction.

The second project investigated the effects of boron nitride substrates on the prop- erties of gold clusters. Experimentalists have deposited gold quantum dots onto boron-nitride nanotubes and were interested in a theoretical explanation for the dif- ferent 2D and 3D structures. For the calculations 2D and 3D, Au6, Au10, Au12, Au14 and Au16 clusters were selected. Their properties were analyzed in a free-standing configuration and on a substrate of h-BN.

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