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[{"key": "dc.contributor.advisor", "value": "Maasilta, Ilari", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.advisor", "value": "Mastom\u00e4ki, Jaakko", "language": "", "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "Lankinen, Aaro", "language": "", "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2021-12-22T05:43:52Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2021-12-22T05:43:52Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2021", "language": "", "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/79111", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Koska grafeeni on aito kaksiulotteinen materiaali, sen avulla voidaan tutkia\nk\u00e4yt\u00e4nn\u00f6ss\u00e4 teorioiden ennustamaa k\u00e4ytt\u00e4ytymist\u00e4 sellaisissa j\u00e4rjestelmiss\u00e4. Yksi\nerityisen kiinnostava ilmi\u00f6 on l\u00e4mm\u00f6njohtavuuden lasku kun materiaaliin luodaan\ns\u00e4\u00e4nn\u00f6llinen reikien joukko. T\u00e4ll\u00f6in puhutaan fononikiteest\u00e4.\n\nT\u00e4ss\u00e4 pro gradu -tutkielmassa kehitettiin elektronisuihkulitografiaan pohjautuva prosessi, jolla voidaan valmistaa fononikiteit\u00e4 useilla eri hilan parametreill\u00e4.\nLis\u00e4ksi kokeiltiin grafeenipinnan puhdistusta reaktiivisen ionietsauksen (RIE) avulla.\nValmiit grafeenifononikidelaitteet kuvannettiin optisen, elektronisuihku-, heliumionija atomivoimamikroskopian keinoin, sek\u00e4 karakterisoitiin s\u00e4hk\u00f6isesti differentiaalikonduktanssin mittauksilla nestetypen l\u00e4mp\u00f6tilasta 75 K nesteheliumin l\u00e4p\u00f6tilaan 4 K.\nTy\u00f6ss\u00e4 n\u00e4ytettiin, ett\u00e4 valmistusmenetelm\u00e4ll\u00e4 voidaan tuottaa vakaita rakenteita,\njoissa pienimm\u00e4t kohdat ovat kymmenien nanometrien luokkaa, ja RIE-puhdistus\nparansi grafeenipinnan laatua kvalitatiivisesti. Grafeenifononikidelaitteiden differentiaalikonduktanssissa n\u00e4htiin huomattava aleneminen, kun j\u00e4nnitebias oli nolla\nalhaisemmilla l\u00e4mp\u00f6tiloilla. T\u00e4m\u00e4 mahdollistaa tulevissa mittauksissa grafeenin\nl\u00e4mm\u00f6nmittauksen lokaalisti. Lis\u00e4\u00e4 tutkimusta tarvitaan, jotta t\u00e4llaisten laitteiden\nl\u00e4mm\u00f6njohtavuus saadaan mitattua alle 4 K:n l\u00e4mp\u00f6tiloissa.", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "Graphene, as a true 2D material, presents the possibility of studying in practice\nmany theoretical models for the behaviour of such systems. One area of particular\ninterest is the suppression of thermal conductance resulting from the introduction of\na periodic array of holes into a material, then known as a phononic crystal (PnC).\n\nIn this thesis work, an electron-beam lithography based process for fabricating\nPnCs of varying lattice parameters in graphene was developed. Additionally, a\nmethod for cleaning carbon contamination off graphene surfaces by reactive ion\netching (RIE) was tested. The resulting graphene PnC (GPnC) devices were imaged\nthrough optical, scanning electron, helium ion and atomic force microscopy, as well\nas electrically characterized through differential conductance measurements at temperatures ranging from liquid nitrogen 75 K to liquid helium 4 K. The fabrication\nmethod was demonstrated to be capable of producing stable structures with feature\nsizes down to tens of nanometers, and the RIE cleaning method showed qualitative\nimprovement of the graphene surfaces. Differential conductance of GPnC devices displayed a significant decrease at zero voltage bias with decreasing temperature, which\nprovides a way for local thermometry of graphene in future work. Further research is\nrequired to measure the thermal conductance of such devices at temperatures below\n4 K.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Miia Hakanen (mihakane@jyu.fi) on 2021-12-22T05:43:52Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2021-12-22T05:43:52Z (GMT). No. of bitstreams: 0\n Previous issue date: 2021", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "76", "language": "", "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.format.mimetype", "value": "application/pdf", "language": null, "element": "format", "qualifier": "mimetype", "schema": "dc"}, {"key": "dc.language.iso", "value": "eng", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": "en", "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "phononic crystal", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "electron-beam lithography", "language": "", "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "Graphene phononic crystals fabricated with electron-beam lithography", "language": "", "element": "title", "qualifier": null, "schema": "dc"}, {"key": "dc.type", "value": "master thesis", "language": null, "element": "type", "qualifier": null, "schema": "dc"}, {"key": "dc.identifier.urn", "value": "URN:NBN:fi:jyu-202112226093", "language": "", "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Pro gradu -tutkielma", "language": "fi", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.type.ontasot", "value": "Master\u2019s thesis", "language": "en", "element": "type", "qualifier": "ontasot", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Matemaattis-luonnontieteellinen tiedekunta", "language": "fi", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Faculty of Sciences", "language": "en", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Fysiikan laitos", "language": "fi", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Department of Physics", "language": "en", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "Jyv\u00e4skyl\u00e4n yliopisto", "language": "fi", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": "en", "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Physics", "language": "en", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "yvv.contractresearch.funding", "value": "0", "language": "", "element": "contractresearch", "qualifier": "funding", "schema": "yvv"}, {"key": "dc.type.coar", "value": "http://purl.org/coar/resource_type/c_bdcc", "language": null, "element": "type", "qualifier": "coar", "schema": "dc"}, {"key": "dc.rights.accesslevel", "value": "openAccess", "language": null, "element": "rights", "qualifier": "accesslevel", "schema": "dc"}, {"key": "dc.type.publication", "value": "masterThesis", "language": null, "element": "type", "qualifier": "publication", "schema": "dc"}, {"key": "dc.subject.oppiainekoodi", "value": "4021", "language": "", "element": "subject", "qualifier": "oppiainekoodi", "schema": "dc"}, {"key": "dc.subject.yso", "value": "grafeeni", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "fononit", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "graphene", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "phonons", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.format.content", "value": "fulltext", "language": null, "element": "format", "qualifier": "content", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}, {"key": "dc.type.okm", "value": "G2", "language": null, "element": "type", "qualifier": "okm", "schema": "dc"}]
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