Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 136 for “"Ultra-high vacuum"”.
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Surface studies in ultra high vacuum
An ultra high vacuum system capable of attaining pressures of 10-12 mm Hg was used for thermal desorption experiments. The metal chosen for these experiments was tantalum because of its suitability for thermal desorption experiments and because relatively little work has been done using this metal. …
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Large-scale graphene transfer in ultra-high vacuum and design of a low temperature ultra-high vacuum scanning tunneling microscope
… large-scale graphene onto clean surfaces in an ultra-high vacuum scanning tunneling microscope chamber via a modified direct contact transfer method. A polyethylene terephthalate (PET) film was chosen as the material for supporting graphene during the in-situ transfer. Both a scanning electron …
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Ultra-High Vacuum Studies of Model Boundary Layer Lubricants
… onto single-crystal metal surfaces under ultra-high vacuum conditions. Chapter 3 presents results from the adsorption of a set of straight-chain carboxylic acids and perfluorinated carboxylic acids onto the Ag(110) surface. The carboxylic acids are found to desorb reversibly from the clean …
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Silicon Nanoelectronic Devices Fabricated by Ultra-High Vacuum, Scanning Tunneling Microscope Nanolithography
… density (∼ 1 x 1014 cm-2) is significantly higher than modulation-doped structures. This allows the lateral patterning of low-dimensional devices without the formation of undesirable carrier depletion regions. STM-patterned nanowires 12-200 nm wide and 750 nm long patterned by STM …
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The design and construction of an ultra-high vacuum field-ion microscope.
Thesis: M.S., Massachusetts Institute of Technology, Department of Metallurgy and Materials Science, 1970
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Modification of an ultra-high-vacuum scanning tunneling microscope for silicon nanostructure fabrication
In this thesis, two major modifications to an ultra-high-vacuum scanning tunneling microscope system are described: an update to the cooling plate structure for more effective cooling of the dipstick and sample holder, and the installation of a capillary doser for concentrating the precursor gas to …
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Sulfurizing and selenizing metal films in ultra-high vacuum by hydride gas kinetic control
Molecular beam epitaxy (MBE) is an important, well-established method for creation of thin films. The addition of gaseous sources of hydrogen sulfide and hydrogen selenide is not currently a well-documented or common modification to such systems. While the thermodynamics of using such sources for …
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Growth of erbium-doped Si/SiGe double heterostructures by ultra-high vacuum chemical vapor deposition
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997.
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Scanning tunneling microscopy and spectroscopy of tip-induced direct writing of nanometallization in ultra-high vacuum
This thesis discusses scanning tunneling microscopy (STM) nanometallization on Si(100):H of HfB2 and MgB2. We first give an introduction to graphene nanoribbons (GNRs) along with STM and the techniques therein. We found that with STM, self-standing nanoscale features including dots, wires, and 3D …
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Scanning tunneling microscopy and spectroscopy of wet chemical synthesized porous graphene nanoribbons in ultra-high vacuum
The student, Kaitlyn Parsons, accepted the attached license on 2018-06-29 at 12:21.
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Putting the Needle to the Haystack: Submolecular Structure Elucidation with Atomic Force Microscopy in Ultra High Vacuum
… These classes of molecules can take on a highly ordered quasi-crystallin state when being adsorbed onto a substrate. Different classes of there are studied, as well as the influence of difference substrates like gold and silver on their assembling behavior. When irradiated with electrons, …
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The ultra-selective hydrogenation of Furfural on PtCu supported bimetallic nanoparticles and on Pt(111) under ultra-high vacuum
… were carried out at pressures ranging from ultra-high vacuum to 20 bar. Temperature Programmed Desorption data in conjunction with Scanning Tunnelling Microscopy suggest that the decarbonylation of furfural on clean Pt(111) and the hydrogenation of furfural on hydrogen pre-covered Pt(111) is …
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In-Situ Studies of Copper Nanoparticles Using a Novel Tandem Ultra-High Vacuum Particle Production Chamber Transmission Electron Microscope
… are arguably a new phase of matter whose high grain-boundary-to-volume ratio leads to new and enhanced material properties. Previously, these materials have been difficult to study because of their sensitivity to contaminating atmospheres. We have built a novel apparatus, an ultra-clean …
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Scanning tunneling microscopy investigations of transition metal dichalcogenide 1t-tantalum disulfide and zigzag-shape graphene nanoribbons in ultra-high vacuum
… layered materials onto a desired substrate under ultra-high vacuum (UHV), to largely prevent potential solvent and atmospheric contamination. STM imaging and scanning tunneling spectroscopy (STS) measurements provide preliminary results on lattice structure of possibly monolayer or few- layer …
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Stress evolution during growth and atomic-scale surface structure effects in transition-metal thin films
Thin films are defined by an extremely high ratio of the in-plane dimensions to the thickness, resulting in very high surface-to-volume ratios. For this reason, the surface characteristics of a film play an important role in the properties of the film as a whole. This research focused on the …
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Controlling CoSi2 formation temperature by reactive deposition
When cobalt is evaporated under ultra high vacuum conditions onto a heated silicon substrate, the reaction between the cobalt and the silicon starts immediately and cobalt silicides are formed directly - a technique referred to as reactive deposition. This procedure was used to grow silicide films …
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The Interaction of Simple Gases with Hot Metal Filaments
… tantalum filaments has also been studied in an ultra high vacuum system. The study of the surface ionisation of iodine and the methyl compounds in the magnetron revealed the mechanisms of ion formation for the bromide, cyanide and iodide negative ions from these compounds. Adsorption and …
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Characterization of graphene-substrate interactions using scanning tunneling microscopy
… those effects in this dissertation. We use the ultra-high vacuum scanning tunneling microscope to study the interface between monolayer graphene flakes and various technologically relevant semiconducting substrates (GaAs, InAs, Si) at room temperature. We observe an electronic semi-transparency …
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Study of Breakdown/arcing for High Power RF Antennas on Fusion Applications
… which allows the electrodes to achieve higher hold-off voltages. To reveal the mechanism by which chemicals modify field emitters on high voltage electrodes a different system with ultra high vacuum, and in-situ diagnostics is required. Further study is recommended.
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