This research project is part of a larger Canadian endeavour to evaluate feasibility of using new nanocatalyst formulations for Fischer-Tropsch synthesis (FTS) to convert fossil-derived or renewable gaseous fuels into green diesel. The green diesel is a clean fuel (with no aromatics and sulfur compounds) suitable for the commonly used transportation system. The catalyst investigated is cobalt metal supported on carbon nanotubes (CNTs). The physical properties of CNTs have improved the common cobalt catalyst currently used in industry. Carbon nanotubes have high surface area, a very stable for FTS activity and, contrary to other common supports, do not interact with the catalyst active phase to produce undesirable compounds. Moreover, CNTs differ from graphite in their purity and by their cylindrical form, which increases the metal dispersion and allows confinement of the particles inside the tubes. Thus, carbon nanotubes as a new type of carbon material have shown interesting properties, favoring catalytic activity for FTS cobalt catalyst. Their surface area can be modified from 170 to 214 m^2/g through acid treatment. The CNT support lowers the amount of Ru promoter needed to increase the catalyst activity up to 80 % CO conversion and potassium promoter increases the selectivity for á-olefins. The olefin to paraffin (O/P) ratio for Co/CNT and CoK/CNT are 0.76 and 0.90, respectively. Moreover, the Co-Fe bimetallic catalysts supported on CNT have proved to be much more attractive in terms of alcohol formation, up to 26.3 % for the Co10Fe4/CNT. The structural characteristics of CNTs have shown to be suitable for use as catalytic support materials for FTS using microemulsion preparation method as applied to produce nanoparticle catalysts. Microemulsion technique results show uniform nanoparticle that are easy to reduce. In addition, the confinement of the particles inside the CNT has improved the lifetime of the catalyst by decreasing the rate of sintering. The deactivation rate at high FTS activity is linear (XCO = -0.13 t(hr) + 75) and at low FTS activity is related to a power law expression of order 11.4 for the cobalt particles outside the tubes and 30.2 for the cobalt particles inside the tube. The optimized catalyst studied was the CoRuK/CNT catalyst. The best kinetic model to describe the CoRuK/CNT catalyst is: 18.5 x 10 ^-5 PH2^0.39/ (1 + 7.2 10 ^-2 PCO^0.72 PH2^0.1)^2.

Endogenously generated H2S has been found not just a toxic substance but may play positive roles, such as the neuromodulator and vasorelaxant in the physiological system since 1990s. Then the precise control of the amount of Hydrogen Sulfide in the animal body raises great interests recently. However, the traditional methods for the Hydrogen Sulfide measurement need a large amount of tissue samples and take a complex procedure; it is impossible to develop any in-vivo real-time approach to measure H2S along the avenue of these methods. There is a great significance to develop new methods toward the measurement of Hydrogen Sulfide in in-vivo, real time, non- or less invasive manner with high resolution. One general idea to make the measurement less invasive is to take blood as sample i.e., to measure Hydrogen Sulfide in blood. <p>The study presented in this thesis aimed to conceive of new measurement methods for Hydrogen Sulfide in an aqueous solution along with their experimental verification. Though the blood sample will eventually be taken, the present study focused on an aqueous solution, which is a first step towards the final goal to measure Hydrogen Sulfide in blood. The study conducted a thorough literature review, resulting in the proposal of five methods, including: (i) the Hydrogen Sulfide measurement by Atomic Force Microscopy, (ii) the H2S measurement by Raman spectroscopy directly, (iii) the Hydrogen Sulfide measurement by Gas Chromatography/Mass Spectroscopy directly (with the static headspace technique), (iv) the Hydrogen Sulfide measurement by Mass Spectroscopy with Carbon Nanotubes, and (v) the Hydrogen Sulfide measurement by Raman spectroscopy with Carbon Nanotubes. The experiments for each of these methods were carried out, and the results were analyzed. Consequently, this study shows that method (v) is very promising to measure low concentration Hydrogen Sulfide in an aqueous solution, especially with the concentration level down to 10 μM and the presence of a linear relationship between the Hydrogen Sulfide concentration and its luminescent intensity.

Optical transition energies are widely used for providing experimental insight into the electronic band structure of single-wall carbon nanotubes (SWCNTs). While the first and second optical transitions in semiconducting carbon nanotubes have already been heavily studied, due to experimental difficulties in accessing the relevant excitation energy region, little is known about higher lying transitions. Here, I present measurements of the third and fourth optical transitions of small-diameter (0.7-1.2 nm), semiconducting single-wall carbon nanotubes via resonant Raman spectroscopy in the visible deep blue region (415-465 nm) and photoluminescence excitation spectroscopy in the ultraviolet and visible blue optical regions (280-488 nm). Diameter-dependent Raman radial breathing mode features, as well as resonant energy excitation maxima determined by Raman and photoluminescence measurements, are assigned to specific (n,m) nanotube species. The Raman intensity within a given 2n+m branch is found to increase with decreasing chiral angle, consistent with similar measurements for lower order optical states. Additionally, increased excitation line widths and weaker Raman intensities are observed as higher lying transitions are accessed for a given nanotube, in agreement with previous Raman measurements. Chiefly, a scaling law analysis that removes the chiral-angle-dependent contribution to the optical transition energy indicates that the third and fourth transition energies exhibit a significant deviation from the energy trend line observed for the first and second optical transitions, when the transition energies are plotted as a function of nanotube diameter. This deviation can be understood in the context of a change in the competition between exchange and excitonic correction terms. Furthermore, for semiconducting SWCNTs with diameters less than 0.9 nm, an additional deviation is observed that is interpreted as the first observation of crossing-over of the third and fourth transition energy trend lines for a given 2n+m branch and a chirality dependence in the many-body excitonic effects that becomes significant at high nanotube curvatures.

Los nanotubos de carbono (CNTs, carbon nanotubes) son moléculas tubulares cuyo diámetro es de escala nanométrica y cuyas paredes están formadas por capas monoatómicas de carbono. Su estructura en combinación con su morfología unidimensional confieren unas propiedades muy especiales que hacen de los CNTs un material muy atractivo para el desarrollo de amplia gama de aplicaciones. En el marco de la micro y nanotecnología, los CNTs son un material muy prometedor para la fabricación de dispositivos y sistemas, por ejemplo, en el campo de la nanoelectrónica, los sensores o los sistemas nanoelectromecánicos (NEMS, del inglés nanoeletcromechanical systems). Sin embargo, dado que aún no se han estandarizado procesos para su síntesis controlada, su integración sigue siendo un reto. Esta tesis fue concebida para avanzar en la integración CNTs en distintos micro y nanodispositivos. El trabajo realizado aborda la ingeniería de procesos, el diseño de dispositivos, y la fabricación y la caracterización de esos dispositivos. Se plantearon dos objetivos principales. El primero fue el adquirir el conocimiento de la síntesis de CNTs mediante la técnica de depósito químico desde fase vapor por calentamiento rápido (RTCVD, rapid termal chemical vapour deposition) y desarrollar procesos para la síntesis de CNTs de una estructura concreta y en una determinada configuración. El segundo objetivo fue el desarrollo de procesos de fabricación para la integración de CNTs en dispositivos basados en diferentes tecnologías y con diferentes funcionalidades. A pesar de la problemática inherente al desarrollo de los procesos tecnológicos, se cumplieron la mayor parte de los objetivos inicialmente propuestos. La síntesis de CNTs se logró mediante catalizadores convencionales (principalmente hierro y níquel) y mediante catalizadores no convencionales (platino). Cabe destacar que los procesos de síntesis de CNTs fueron estandarizados a nivel de obleas de 4 pulgadas, tanto para configuraciones de baja densidad de CNTs monocapa (SWCNTs, single-walled carbon nanotubes) como para configuraciones de alta densidad de CNTs multicapa (MWCNTs, multi-walled carbon nanotubes), ya que la síntesis tradicionalmente se realiza a nivel de chip. En cuanto a la integración de CNTs, se optimizaron dos procesos principalmente. Por un lado, se desarrolló una tecnología para la fabricación masiva en oblea de transistores basados en SWCNTs. Mediante esta tecnología se logró la fabricación de 10.000 transistores funcionales en obleas de 4 pulgadas. Por otro lado, se integró gran densidad de MWCNTs sobre los electrodos metálicos de dispositivos que habían sido demostrados para detección bio-electroquímica. La caracterización de estos electrodos demostró que esta actualización de la tecnología mejora el rendimiento de la fabricación y las características electroquímicas de los electrodos respecto a los diseños anteriores. Los resultados presentados en esta tesis son un paso adelante para la Integración a muy gran escala (VLSI, very large system integration) de CNTs. Los procesos que se desarrollaron son de interés en el campo de la nanoelectrónica, en el campo de la bio-sensores electroquímicos, para la fabricación de dispositivos optoelectrónicos y para la fabricación de NEMS. / Carbon nanotubes (CNTs) are tubular molecules which diameters may be smaller than one nanometre and which walls are formed of single carbon atom layers that are arranged in a honey comb lattice. Because of their one dimensional aspect ratio and properties, which are conferred by their structural arrangement, CNTs are a very attractive material for a wide range of applications. In the frame of micro- and nanotechnology, CNTs have been demonstrated to be very promising for the fabrication of devices and systems for nanoelectronics, sensors or nanoelectromechanical systems (NEMS). However, standardised processes for their fully controlled synthesis and their successful integration into those systems are still challenging. This thesis was conceived to advance on the wafer scale integration of CNTs into micro- and nanodevices. Performed work dealt with process engineering, device design, device fabrication and device characterization. Two major goals were pursued: (i) to acquire the knowhow on the synthesis of CNTs by rapid thermal chemical vapour deposition (RTCVD) to develop recipes to synthesize certain in structure CNTs and certain in morphology CNT arrays, and (ii) the wafer scale integration of CNTs into devices with different functionalities and technological processes by conventional fabrication steps. Despite the inherent problematic of the technological process developments, most of the initially foreseen goals were fulfilled. The CNT synthesis was achieved by conventional (mainly iron and nickel) and by nonconventional (platinum) catalyst materials. It is remarkable how the CNT RTCVD synthesis processes were standardized at 4 inch wafer scale for either low density of single-walled (SW) CNT arrays or for dense, vertically aligned multi-walled (MW) CNT arrays, since the CNT synthesis is normally performed at chip level. Regarding the wafer scale integration of the CNTs, two main processes were optimised. On the one side, SWCNTs were integrated in the fabrication of CNT-FETs. This technology resulted in the fabrication of 10,000 functional CNT-FETs on 4 inch wafers in a sole fabrication process. Later on, the technology was upgraded for the fabrication of passivated CNT-FET devices for electrochemical sensing. On the other side, dense arrays of MWCNTs were integrated into devices based on metallic electrodes that had previously been demonstrated for bio-electrochemical sensing. These electrodes were demonstrated to improve the fabrication yield and the electrochemical characteristics with respect to the previous designs. Presented in this thesis results are a step forward to the Very Large Scale Integration (VLSI) of CNTs. The developed processes are of interest in the field of nanoelectronics, in the field of bio-electrochemical sensing, for the fabrication of optoelectronic devices and for the fabrication NEMS.

Carbon nanotubes (CNTs) are advanced materials that have numerous novel and useful properties. Controlling the synthesis and properties of CNTs is the major challenge toward their future applications. This thesis addresses this challenge with several contributions. This thesis begins with the brief introduction of CNTs, including the history of their discovery, their geometric structure, unique properties and potential applications. Then focus is laid on the subsequent three sections: characterization, synthesis, and manipulation of CNTs. Chapter 2 describes three characterization tools: AFM, SEM and Raman, which are commonly used to analyze CNTs and other nanomaterials. They offer both qualitative and quantitative information on many physical properties including size, morphology, surface texture and roughness. Also, they can be used to determine the structure of CNTS. Chapter 3 addresses the synthesis of CNTS, because synthesis is an important and indispensible process to study CNTs experimentally. Specifically, two controllable synthesis techniques are realized, which are capable to produce iron catalyst nanoparticles for single-walled carbon nanotube (SWNT) growth. Iron nanoparicles of different sizes obtained from both wet chemistry and electrodeposition can be used for diameter-controlled synthesis of SWNTs. Following synthesis, two manipulation methods of CNTs are discussed in Chapter 4. Firstly, effort of electrical breakdown of CNTs is introduced. Both SWNTs and MWNTs (Multi-walled carbon nanotubes) are cut using this method. Moreover, SWNT kink is shown using AFM tip manipulation. These two manipulation methods provide us a possibility to fabricate large cavity from a MWNT for our purposes. In the end of this thesis, conclusions on my master work in research field of CNTs are drawn and future research directions are proposed.

Graphene-based materials have generated tremendous interest in the past decade. Manipulating their characteristics using wet-chemistry methods holds distinctive value, as it provides a means towards scaling up, while not being limited by yield. The majority of this thesis focuses on the surface functionalization of graphene oxide (GO), which has drawn tremendous attention as a tunable precursor due to its readily chemically manipulable surface and richly functionalized basal plane. Firstly, a room-temperature based method is presented to reduce GO stepwise, with each organic moiety being removed sequentially. Characterization confirms the carbonyl group to be reduced first, while the tertiary alcohol is reduced last, as the optical gap decrease from 3.5 eV down to 1 eV. This provides greater control over GO, which is an inhomogeneous system, and is the first study to elucidate the order of removal of each functional group. In addition to organically manipulating GO, this thesis also reports a chemical methodology to inorganically functionalize GO and tune its wetting characteristics. A chemical method to covalently attach fluorine atoms in the form of tertiary alkyl fluorides is reported, and confirmed by MAS 13C NMR, as two forms of fluorinated graphene oxide (FGO) with varying C/F and C/O ratios are synthesized. Introducing C-F bonds decreases the overall surface free energy, which drastically reduces GO’s wetting behavior, especially in its highly fluorinated form. Ease of solution processing leads to development of sprayable inks that are deposited on a range of porous and non-porous surfaces to impart amphiphobicity. This is the first report that tunes the wetting characteristics of GO. Lastly as a part of a collaboration with ConocoPhillips, another class of carbon nanomaterials - carbon nanotubes (CNTs), have been inorganically functionalized to repel 30 wt% MEA, a critical solvent in CO2 recovery. In addition to improving the solution processability of CNTs, composite, homogeneous solutions are created with polysulfones and polyimides to fabricate CNT-polymer nanocomposites that display contact angles greater than 150o with 30 wt% MEA. This yields materials that are inherently supersolvophobic, instead of simply surface treating polymeric films, while the low density of fluorinated CNTs makes them a better alternative to superhydrophobic polymer materials.

Carbon nanotubes (CNTs) are advanced materials that have numerous novel and useful properties. Controlling the synthesis and properties of CNTs is the major challenge toward their future applications. This thesis addresses this challenge with several contributions. This thesis begins with the brief introduction of CNTs, including the history of their discovery, their geometric structure, unique properties and potential applications. Then focus is laid on the subsequent three sections: characterization, synthesis, and manipulation of CNTs. Chapter 2 describes three characterization tools: AFM, SEM and Raman, which are commonly used to analyze CNTs and other nanomaterials. They offer both qualitative and quantitative information on many physical properties including size, morphology, surface texture and roughness. Also, they can be used to determine the structure of CNTS. Chapter 3 addresses the synthesis of CNTS, because synthesis is an important and indispensible process to study CNTs experimentally. Specifically, two controllable synthesis techniques are realized, which are capable to produce iron catalyst nanoparticles for single-walled carbon nanotube (SWNT) growth. Iron nanoparicles of different sizes obtained from both wet chemistry and electrodeposition can be used for diameter-controlled synthesis of SWNTs. Following synthesis, two manipulation methods of CNTs are discussed in Chapter 4. Firstly, effort of electrical breakdown of CNTs is introduced. Both SWNTs and MWNTs (Multi-walled carbon nanotubes) are cut using this method. Moreover, SWNT kink is shown using AFM tip manipulation. These two manipulation methods provide us a possibility to fabricate large cavity from a MWNT for our purposes. In the end of this thesis, conclusions on my master work in research field of CNTs are drawn and future research directions are proposed.

Endogenously generated H2S has been found not just a toxic substance but may play positive roles, such as the neuromodulator and vasorelaxant in the physiological system since 1990s. Then the precise control of the amount of Hydrogen Sulfide in the animal body raises great interests recently. However, the traditional methods for the Hydrogen Sulfide measurement need a large amount of tissue samples and take a complex procedure; it is impossible to develop any in-vivo real-time approach to measure H2S along the avenue of these methods. There is a great significance to develop new methods toward the measurement of Hydrogen Sulfide in in-vivo, real time, non- or less invasive manner with high resolution. One general idea to make the measurement less invasive is to take blood as sample i.e., to measure Hydrogen Sulfide in blood. <p>The study presented in this thesis aimed to conceive of new measurement methods for Hydrogen Sulfide in an aqueous solution along with their experimental verification. Though the blood sample will eventually be taken, the present study focused on an aqueous solution, which is a first step towards the final goal to measure Hydrogen Sulfide in blood. The study conducted a thorough literature review, resulting in the proposal of five methods, including: (i) the Hydrogen Sulfide measurement by Atomic Force Microscopy, (ii) the H2S measurement by Raman spectroscopy directly, (iii) the Hydrogen Sulfide measurement by Gas Chromatography/Mass Spectroscopy directly (with the static headspace technique), (iv) the Hydrogen Sulfide measurement by Mass Spectroscopy with Carbon Nanotubes, and (v) the Hydrogen Sulfide measurement by Raman spectroscopy with Carbon Nanotubes. The experiments for each of these methods were carried out, and the results were analyzed. Consequently, this study shows that method (v) is very promising to measure low concentration Hydrogen Sulfide in an aqueous solution, especially with the concentration level down to 10 μM and the presence of a linear relationship between the Hydrogen Sulfide concentration and its luminescent intensity.

This research project is part of a larger Canadian endeavour to evaluate feasibility of using new nanocatalyst formulations for Fischer-Tropsch synthesis (FTS) to convert fossil-derived or renewable gaseous fuels into green diesel. The green diesel is a clean fuel (with no aromatics and sulfur compounds) suitable for the commonly used transportation system. The catalyst investigated is cobalt metal supported on carbon nanotubes (CNTs). The physical properties of CNTs have improved the common cobalt catalyst currently used in industry. Carbon nanotubes have high surface area, a very stable for FTS activity and, contrary to other common supports, do not interact with the catalyst active phase to produce undesirable compounds. Moreover, CNTs differ from graphite in their purity and by their cylindrical form, which increases the metal dispersion and allows confinement of the particles inside the tubes. Thus, carbon nanotubes as a new type of carbon material have shown interesting properties, favoring catalytic activity for FTS cobalt catalyst. Their surface area can be modified from 170 to 214 m^2/g through acid treatment. The CNT support lowers the amount of Ru promoter needed to increase the catalyst activity up to 80 % CO conversion and potassium promoter increases the selectivity for á-olefins. The olefin to paraffin (O/P) ratio for Co/CNT and CoK/CNT are 0.76 and 0.90, respectively. Moreover, the Co-Fe bimetallic catalysts supported on CNT have proved to be much more attractive in terms of alcohol formation, up to 26.3 % for the Co10Fe4/CNT. The structural characteristics of CNTs have shown to be suitable for use as catalytic support materials for FTS using microemulsion preparation method as applied to produce nanoparticle catalysts. Microemulsion technique results show uniform nanoparticle that are easy to reduce. In addition, the confinement of the particles inside the CNT has improved the lifetime of the catalyst by decreasing the rate of sintering. The deactivation rate at high FTS activity is linear (XCO = -0.13 t(hr) + 75) and at low FTS activity is related to a power law expression of order 11.4 for the cobalt particles outside the tubes and 30.2 for the cobalt particles inside the tube. The optimized catalyst studied was the CoRuK/CNT catalyst. The best kinetic model to describe the CoRuK/CNT catalyst is: 18.5 x 10 ^-5 PH2^0.39/ (1 + 7.2 10 ^-2 PCO^0.72 PH2^0.1)^2.

Multiwalled carbon nanotubes (MWNTs) are shown to be ballistic conductors at room temperature, with mean free paths of the order of tens of microns. The electrical transport measurements are performed both in air and in high vacuum in the transmission electron microscope on nanotubes pointing out of a nanotube-containing fiber that contact with a liquid metal. These measurements demonstrate that metallic MWNTs are one dimensional conductor that have quantized conductance nearly 1G0 (~{!V~}(12.9 K~{ and 8~})-1). The intrinsic resistance per unit length is found to be smaller than 100 ~{ and 8~}/~{ and L~}m, indicating a mean free path l> 65 ~{ and L~}m. The nanotube-metal contact resistances are in the range from 0.1 to 1 k~{ and 8 and L~}m. Contact scattering can explain why the measured conductances are about half of the expected theoretical value of 2G0. Current-to-voltage characteristic are in accord with the electronic structure. The nanotubes can survive high current (up to 1 mA, i.e., current density on the order of 109 A/cm2). In situ electron microscopy shows that a relative large fraction of the nanotubes do not conduct (even at high bias), consistent with the existence of semiconducting nanotubes. Discrepancies with other measurements are most likely due to damage caused to the outer layer(s) of the nanotubes during processing. The measured mean free path of clean, undamaged arc-produced MWNTs is several orders of magnitude greater than that for metals, making this perhaps the most significant property of carbon nanotubes.