Controlling Nanostructures for in-situ TEM Characterization

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dc.contributor.advisorCumings, Johnen_US
dc.contributor.authorNilsson, Hanna Magdalenaen_US
dc.contributor.departmentMaterial Science and Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2016-06-22T05:34:47Z
dc.date.available2016-06-22T05:34:47Z
dc.date.issued2015en_US
dc.description.abstractLow dimensional nanostructures, such as nanotubes and 2D sheets, have unique and promising material properties both from a fundamental science and an application standpoint. Theoretical modelling and calculations predict previously unobserved phenomena that experimental scientists often struggle to reproduce because of the difficulty in controlling and characterizing the small structures under real-world constraints. The goal of this dissertation is to controlling these structures so that nanostructures can be characterized in-situ in transmission electron microscopes (TEM) allowing for direct observation of the actual physical responses of the materials to different stimuli. Of most interest to this work are the thermal and electrical properties of carbon nanotubes, boron nitride nanotubes, and graphene. The first topic of the dissertation is using surfactants for aqueous processing to fabricate, store, and deposit the nanostructures. More specifically, thorough characterization of a new surfactant, ammonium laurate (AL), is provided and shows that this new surfactant outperforms the standard surfactant for these materials, sodium dodecyl sulfate (SDS), in almost all tested metrics. New experimental set-ups have been developed by combining specialized in-situ TEM holders with innovative device fabrication. For example, electrical characterization of graphene was performed by using an STM-TEM holder and depositing graphene from aqueous solutions onto lithographically patterned, electron transparent silicon nitride membranes. These experiments produce exciting information about the interaction between graphene and metal probes and the substrate that it rests on. Then, by adding indium to the backside of the membrane and employing the electron thermal microscopy (EThM) technique, the same type of graphene samples could be characterized for thermal transport with high spatial resolution. It is found that reduced graphene oxide sheets deposited onto a silicon nitride membrane and displaying high levels of wrinkling have higher than expected electrical and thermal conduction properties. We are clearly able to visualize the ability of graphene to spread heat away from an electronic hot spot and into the substrate.en_US
dc.identifierhttps://doi.org/10.13016/M2KJ4Z
dc.identifier.urihttp://hdl.handle.net/1903/18140
dc.language.isoenen_US
dc.subject.pqcontrolledMaterials Scienceen_US
dc.subject.pqcontrolledPhysicsen_US
dc.subject.pqcontrolledEngineeringen_US
dc.subject.pquncontrolledCarbon nanotubesen_US
dc.subject.pquncontrolledElectrical resistanceen_US
dc.subject.pquncontrolledGrapheneen_US
dc.subject.pquncontrolledNanostructuresen_US
dc.subject.pquncontrolledThermal conductivityen_US
dc.subject.pquncontrolledTransmission electron microscopyen_US
dc.titleControlling Nanostructures for in-situ TEM Characterizationen_US
dc.typeDissertationen_US

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