4.1. Nanomachining with Scanning Probes 1831 4.2. Soft Lithography 1832 4.3. Embossing with Rigid Masters 1835 4.4. Near-Field Phase-Shifting Photolithography 1835 4.5. Topographically Directed Photolithography 1837 4.6. Topographically Directed Etching 1837 4.7. Lithography with Neutral Metastable Atoms 1838 4.8. Approaches to Size Reduction 1839 5. Techniques for Making Regular or Simple Patterns 1839

https://www.engr.colostate.edu/ECE581/fall07/xia%20chem%20rev%2099.pdf

Unconventional Methods for Fabricating and Patterning Nanostructures.

The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies.

https://www.tandfonline.com/doi/pdf/10.1080/13102818.2015.1008192

An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

A buckminsterfullerene (C60)-based primary ion beam system has been developed for routine application in TOF-SIMS analysis of organic materials. The ion beam system is described, and its performance is characterized. Nanoamp beam currents of C60+ are obtainable in continuous current mode. C602+ can be obtained in pulsed mode. At 10 keV, the beam can be focused to less than 3 μm with 0.1 nA currents. TOF-SIMS studies of a series of molecular solids and a number of polymer systems in monolayer and thick film forms are reported. Very significant enhancement of secondary ion yields, particularly at higher mass, were observed using 10-keV C60+ for all samples other than PTFE, as compared to those observed from 10 keV Ga+ primary ions. Three materials (PS2000, Irganox 1010, PET) were studied in detail to investigate primary ion-induced disappearance (damage) cross sections to determine the increase in secondary ion formation efficiency. The C60 disappearance cross sections observed from monolayer film PS2000 an...

A C60 Primary Ion Beam System for Time of Flight Secondary Ion Mass Spectrometry: Its Development and Secondary Ion Yield Characteristics

Mass spectrometry of polymers and polymer surfaces.

Substitutional doping of transition metal dichalcogenides (TMDs) may provide routes to achieving tunable p–n junctions, bandgaps, chemical sensitivity, and magnetism in these materials. In this study, we demonstrate in situ doping of monolayer molybdenum disulfide (MoS2) with manganese (Mn) via vapor phase deposition techniques. Successful incorporation of Mn in MoS2 leads to modifications of the band structure as evidenced by photoluminescence and X-ray photoelectron spectroscopy, but this is heavily dependent on the choice of substrate. We show that inert substrates (i.e., graphene) permit the incorporation of several percent Mn in MoS2, while substrates with reactive surface terminations (i.e., SiO2 and sapphire) preclude Mn incorporation and merely lead to defective MoS2. The results presented here demonstrate that tailoring the substrate surface could be the most significant factor in substitutional doping of TMDs with non-TMD elements.

Manganese Doping of Monolayer MoS2: The Substrate Is Critical

By using mass spectrometry to analyze the atomic and molecular secondary ions that are emitted from a solid surface when bombarded with ions, one obtains detailed information about the chemical composition of the surface. A time-of-flight mass spectrometer is especially suitable for the analysis of secondary ions because of its high transmission, high mass resolution, and ability to detect ions of different masses simultaneously. By using a finely focused primary ion beam it is also possible to analyze microareas and generate surface images with a lateral resolution of 0.1 μm or less. Static time-of-flight secondary ion mass spectrometry (TOF-SIMS) allows monolayer imaging and local analysis of monolayers with high sensitivity, a wide mass range, high mass resolution, and high lateral resolution. Besides information on elements and isotopes, the technique yields direct information on the molecular level and can also be used to analyze surface species of high molecular mass that are thermally unstable and cannot be vaporized. The method can be applied to practically all types of materials and sample forms, including insulators in particular. In this article the basic principles of TOF-SIMS are explained, and its analytical capabilities for both large area and imaging applications are illustrated by examples. These include silicon surfaces (both uniform and structured), thermally unstable organic molecules on surfaces, synthetic polymers, and synthetically prepared molecular surface films, particles, and fibers. Emitted neutral particles can also be analyzed by postionization with a laser, and the possibilities of this technique are discussed.

Chemical Analysis of Inorganic and Organic Surfaces and Thin Films by Static Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS)

Die massenspektrometrische Analyse atomarer und molekularer Sekundarionen, die von einer Festkorperoberflache beim Beschus mit Ionen emittiert werden, liefert detaillierte Informationen uber die chemische Zusammensetzung dieser Oberflache. Wegen ihrer hohen Transmission und Massenauflosung, ihres unbegrenzten Massenbereichs und des parallelen Massennachweises sind Flugzeit-Massenspektrometer fur die Sekundarionenanalyse besonders geeignet. Mit feinfokussierten Primarionenstrahlen sind Mikrobereichsanalysen und chemische Oberflachenabbildungen mit Lateralauflosungen <0.1 μm moglich. Mit der statischen Flugzeit-Sekundarionen-Massenspektrometrie (TOF-SIMS) konnen Monolagen abgebildet und sehr empfindlich uber einen grosen Massenbereich mit hoher Massen- und Lateralauflosung lokal analysiert werden. Element- und Isotopen-, aber auch direkte Informationen uber molekulare Bereiche, z.B. uber thermisch labile, nichtverdampfbare hochmolekulare Oberflachenkomponenten, werden erhalten. Das Verfahren ist auf nahezu alle Materialien und Probenformen, insbesondere auch auf Isolatoren anwendbar. Die Grundlagen der TOF-SIMS werden behandelt und die analytischen Moglichkeiten des Verfahrens anhand typischer Beispiele fur grosflachige und abbildende Analysen, unter anderem von homogenen und strukturierten Siliciumoberflachen, thermisch labilen organischen Molekulen auf Oberflachen, synthetischen Polymeren, synthetisierten molekularen Oberflachenschichten sowie Partikeln und Fasern gezeigt. Auf die analytische Nutzung Laser-nachionisierter Neutralteilchen wird ebenfalls eingegangen.

Chemische analyse von anorganischen und organischen oberflachen und von dunnen schichten mit der statischen flugzeit-sekundarionen-massenspektrometrie (tof-sims)

Alfred Benninghoven

Papers

Chemical Analysis of Inorganic and Organic Surfaces and Thin Films by Static Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS)

Chemical Analysis of Inorganic and Organic Surfaces and Thin Films by Static Time‐of‐Flight Secondary Ion Mass Spectrometry (TOF‐SIMS)

Chemische analyse von anorganischen und organischen oberflachen und von dunnen schichten mit der statischen flugzeit-sekundarionen-massenspektrometrie (tof-sims)