A system for the patterning of amines through the thermal decomposition of a thin polymer film was proposed. The polymer was synthesized and films were produced by spin coating. The pyrolysis of both the polymer and the films was studied. The physical properties of the film, such as Tg, were controlled through crosslinking of the polymer and the crosslinking conditions were optimized. Analyses of the reactions that occur on the film as a result of thermal decomposition were studied. These studies seem to indicate that the thin film system studied is viable option toward the patterning of amines. The ability to bind material to the polymer films after deprotection was demonstrated using fluorescent protein and fluorescein isothiocyanate. Micron scale patterns of these fluorescent molecules were created and imaged, successfully demonstrating the viability of the system for patterning. Patterns of polyphenylene vinlyene were produced through the thermal decomposition of a tetrahydrothiophenium chloride salt precursor. Images of the patterns were obtained.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

The primary goal of my dissertation was to build a Scanning Hall Probe Microscope (SHPM) for studying the domain structure of a ferromagnetic semiconductor (Ga[subscript 0.94]Mn[subscript 0.06]). This new semiconductor may be used in the emerging field of spintronics, where both the charge and spin of an electron are utilized. The first part of this dissertation introduces the scanning probe microscopy techniques that are used for our homemade SHPM performance test and images. In chapter 2, general spintronics and ferromagnetic semiconductor are introduced. A compact design of our LT-SHPM is introduced in chapter 3. A unique taper seal based on stainless steel and Cu for opening/closing the vacuum chamber is used for our homemade SHPM. In chapter 4, Hall probes are discussed. In this chapter, ESD (Electrostatic discharge) and its repair work are discussed. Finally, in Chapter 5, SHPM imaging results of Ga[subscript 0.94]Mn[subscript 0.06]As are discussed. We observed stripe domain patterns. We also observed the domain patterns as a function of magnetic field and temperature. / text

This dissertation presents experimental studies on Brownian motion at fast time scales, as well as our recent developments in Thermal Noise Imaging which uses thermal motions of microscopic particles for spatial imaging. As thermal motions become increasingly important in the studies of soft condensed matters, the study of Brownian motion is not only of fundamental scientific interest but also has practical applications. Optical tweezers with a fast position-sensitive detector provide high spatial and temporal resolution to study Brownian motion at fast time scales. A novel high bandwidth detector was developed with a temporal resolution of 30 ns and a spatial resolution of 1 °A. With this high bandwidth detector, Brownian motion of a single particle confined in an optical trap was observed at the time scale of the ballistic regime. The hydrodynamic memory effect was fully studied with polystyrene particles of different sizes. We found that the mean square displacements of different sized polystyrene particles collapse into one master curve which is determined by the characteristic time scale of the fluid inertia effect. The particle’s inertia effect was shown for particles of the same size but different densities. For the first time the velocity autocorrelation function for a single particle was shown. We found excellent agreement between our experiments and the hydrodynamic theories that take into account the fluid inertia effect. Brownian motion of a colloidal particle can be used to probe three-dimensional nano structures. This so-called thermal noise imaging (TNI) has been very successful in imaging polymer networks with a resolution of 10 nm. However, TNI is not efficient at micrometer scale scanning since a great portion of image acquisition time is wasted on large vacant volume within polymer networks. Therefore, we invented a method to improve the efficiency of large scale scanning by combining traditional point-to-point scanning to explore large vacant space with thermal noise imaging at the proximity of the object. This method increased the efficiency of thermal noise imaging by more than 40 times. This development should promote wider applications of thermal noise imaging in the studies of soft materials and biological systems. / text

Near-field light confinement on scanning probe is the backbone technology for near-field imaging with subwavelength resolution that overcomes the diffraction limit by exploiting the properties of evanescent waves. The fusion of the photonics and the latest nanofabrication technology creates emerging frontier for near-field light confinement research with new design approach. The propagation of light can now be controlled by periodical structure at subwavelength scale with low loss in the artificially synthesized dielectric material. New light propagation patterns can now be implemented in subwavelength structure, such as directional free space light focus grating coupler, photonic bandgap material like photonic crystal by permitting light propagation at certain wavelength while prohibiting light outside of bandgap, and nano-slot light resonator for increased light-matter interaction at nanometer scale. Advances in this research area will have tremendous impact on electromagnetic modeling and biomedical technology for probe based subwavelength optical detection. My doctoral research focused on investigating highly efficient, nanofabrication compatible directional light coupling structure and near-field subwavelength light focus through photonic crystal material. The distinct significance of this research was placed on exploitation of the embedded metallic grating coupler of high free space directivity and subwavelength light processing circuit of enhanced near-field transmission rate, the two most dominating basic elements of the scanning optical imaging system. First, I designed a compact elliptical grating coupler based on embedded noble metal such as gold or silver that efficiently interconnects free space with dielectric rectangular waveguide. The dense system integration capability shows the application potential for on-chip interfacing subwavelength light processing circuits and near-field fluorescent biosensors with far-field detection of superb radiation directivity and coupling efficiency. Second, a novel all-dielectric light confinement probe designed by slotted photonic crystal waveguide provides a light confinement mechanism on the lateral plane. The resonating nano-cavities and the λ/4 nano-slot are used to enlarge the light throughput while as the nano-slot waveguide provides single subwavelength center lobe. The impetus of this research is the growing interests by near-field imaging researchers to obtain a low loss visible light confinement probe designs through mass production. / text

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A Pan-style scanning tunneling microscope (STM), with a vertical coarse approach mechanism, was designed, built and tested. The microscope will be operated in ultra-high vacuum and also at cryogenic temperatures (8 K) inside a continuous flow cryostat. Fundamental differences in operating principle exist between the new microscope and the beetle-type inertial sliders [1] that have been the mainstay of the group for the last eight years. While Pan-style microscopes do already exist [2], they remain challenging to build, and an active area of research [3]. This system represents a bold departure from well-trodden paths, and will greatly expand the range of experiments that our group can perform. The operating principles of inertial piezoelectric motors are detailed. Design guidelines for a piezoelectric motor are given, and used in the design of the vertical coarse approach motor. A simple, inexpensive implementation for creating waveforms with an extremely fast fall time is discussed. Motor performance is tested, and a minimum step size of 20nm is found for frequencies ranging from 0 Hz to 3 kHz. The motor operates with high dynamic range: individual 20nm steps can be taken, as well as being able to move at a velocity of 0.4mm s−1. Little is known about the vibrational properties of Pan-style microscopes. Vibrational testing of the microscope revealed the expected scanner bending mode at 1.6 kHz (above the scanner bending mode of our beetles at 1.2 kHz), and a complicated response signal above this frequency. Custom extension springs for an eddy-current damping system are built and tested. A low resonant frequency of 1.8 Hz is found, which is ideal for the application. Initial testing of the STM in ambient conditions is performed on two different surfaces. A moir´e supermesh [4] with periodicity 3nm is observed on a highly-oriented pyrolytic graphite (HOPG) surface, and agrees well with previously published results. Using a flame-annealed Gold on mica surface, a low drift rate of 0.6nm s−1 is observed over a period of 13 minutes. Single-height atomic steps are observed on both surfaces. Additionally, the microscope is shown to be capable of zooming into different features on a surface, and scanning at different length scales. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-06-24 13:06:16.683

The promise to build structures atom by atom that would lead to devices or materials with tuned properties that surpass any material we encounter in the macroscale world inspires more researchers everyday to study nanotechnology. As a direct result of this interest in nanotechnology, manipulation systems with nano or sub-nano scale precision are required to position or pattern matter in smaller scales to study it. However, this manipulation task is not straightforward due to small scale physics, which reduces the effect of weight and inertia, the dominant forces in macroscale, and promotes other forces such as adhesion or electrostatic interactions. Hence, to understand nanoscale physics, the first step to take is to model and characterize the underlying principles. In this context, scanning probe microscopes (SPMs) are suitable tools for experimenting on nanoscale physics, in addition to being good candidates as nanomanipulation systems due to their ability to locally interact with the substrate using the end-effector that they utilize on the order of a few nanometers or below. On the other hand, using SPMs for nanomanipulation has drawbacks as well. Since they utilize a single end-effector to interact with the substrate, the manipulation process is serial hence slow with low throughput. Furthermore, having no real-time visual feedback and the non-linearity of the actuators decrease the precision and the repeatability of the positioning, hence decreasing the reliability of the manipulation. In order to consider SPMs as viable nanomanipulation tools, these challenges of speed and reliability should first be tackled by utilizing smarter algorithms and mechanisms. In this work, we demonstrate two case studies that are used for tackling the speed and reliability challenges of nanomanipulation. As the first case study, an AFM is utilized to position nanoparticles. In the AFM based mechanical contact manipulation of nanoparticles, we demonstrate automated control to increase speed and reliability. In order to achieve the automation, we present models to investigate the physics of nanoparticle manipulation using an AFM cantilever, and use these models to investigate the effect of cantilever selection to manipulation success. We demonstrate particle detection using line-scans and a contact loss detection algorithm using cantilever normal deflection data to decrease the number of images taken during manipulation. We also demonstrate through experimental results that it is possible to push and pull particles on a flat surface into defined patterns autonomously, using an AFM probe tip, and with an error less than the particle diameter, and with success rates as high as 87%. Moreover, an STM is utilized to manipulate surfaces using electrical pulses and high electric fields as a second case study of this thesis. During the STM based electrical non-contact manipulation, utilizing conductive AFM probes as STM end-effectors as a step towards a multiple probe approach is suggested to improve the speed and throughput of the STM manipulation. STM imaging of surfaces using STM tips and conductive AFM probes are demonstrated and algorithms for STM based electrical manipulation of surfaces is presented and experimentally verified. Furthermore, models for STM operation and manipulation using STM tips and AFM probes as end-effectors are developed and the effects of several design parameters on STM based imaging and manipulation that utilizes AFM probes and STM tips are investigated. In addition, a faster and more flexible controller is designed and implemented which allows instant switching between AFM and STM modes, when conductive AFM probes are utilized.