Nanoscience and Microsystems ETDs

Publication Date

8-31-2011

Abstract

We developed a universal, facile and robust method to prepare free-standing, ordered and patternable nanoparticle/polymer monolayer arrays by evaporation-induced self-assembly at a fluid interface. The ultra-thin monolayer nanoparticle/polymer arrays are sufficiently robust that they can be transferred to arbitrary substrates, even with complex topographies. More importantly, the Poly (methyl methacrylate) (PMMA) in the system serves as a photoresist enabling two modes of electron beam (e-beam) nanoparticle patterning. These ultra-thin films of monolayer nanoparticle arrays are of fundamental interest as 2D artificial solids for electronic, magnetic and optical properties and are also of technological interest for a diverse range of applications in micro- and macro-scale devices including photovoltaics, sensors, catalysis, and magnetic storage. By co-assembly with block co-polymers, the nanoparticles were selectively positioned in one specific phase, representing a high throughput route for creating nanoparticle patterns. The self-assembly process was investigated by combined in-situ grazing incidence small angle x-ray scattering (GISAXS) and numerical simulation. By e-beam irradiation of free-standing 2D NP/polymer arrays, anisotropic nanowire arrays have been fabricated. Additionally, preliminary investigation on assembly of binary nanoparticle arrays has also been introduced, serving as promising future directions of interfacial assembly. viii Controlling the rate of spontaneous emission and thus promoting the photon generation efficiency is a key step toward fabrication of Quantum dot based single-photon sources, and harnessing of light energy from emitters with a broad emitting spectrum. Coupling of photo emitters to photonic cavities without perturbing the optical performance of cavities remains as a challenge in study of Purcell effect based on quantum electrodynamics. Taking advantage of interfacial assembly and transfer, we have achieved controlled deposition of quantum dots into high Q photonic microcavities and studied the modification of their optical properties. Anomalous enhanced spontaneous emission and Fabry-Perot resonance have been observed.

Keywords

Monomolecular films., Nanocomposites (Materials), Nanoparticles., Quantum dots., Self-assembly (Chemistry), Photonic crystals.

Sponsors

This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences Grant DE-FG02-02-ER15368; the DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering; the National Institute for NanoEngineering (NINE) program at Sandia National Laboratories; and the Sandia National Laboratories Laboratory Directed Research and Development (LDRD) program. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.'

Document Type

Dissertation

Language

English

Degree Name

Nanoscience and Microsystems

Level of Degree

Doctoral

Department Name

Nanoscience and Microsystems

First Committee Member (Chair)

Datye, Abhaya

Second Committee Member

Luk, Tingshan

Third Committee Member

Grey, John K.

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