{"id":21733,"date":"2011-10-19T13:55:21","date_gmt":"2011-10-19T10:55:21","guid":{"rendered":"http:\/\/www.fyysika.ee\/uudised\/?p=21733"},"modified":"2011-11-01T11:56:22","modified_gmt":"2011-11-01T08:56:22","slug":"dielektrikute-aatomikihtsadestamisest-grafeenile","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=21733","title":{"rendered":"Dielektrikute aatomkihtsadestamisest grafeenile"},"content":{"rendered":"<p>\u00dcheainsa aatomikihi paksune grafeen, mille moodustavad kuusnurkses v\u00f5res olevad s\u00fcsinikuaatomid ja mida loetakse hetkel k\u00f5ige potentsiaalsemaks j\u00e4rglaseks r\u00e4nile tuleviku nanoelektroonikas, on olnud viimastel aastatel ehk enim uuritud materjal. Materjaliteaduses valitsenud \u201cgrafeenibuumile\u201d andis l\u00e4inud aastal veelgi hoogu juurde 2010. aasta Nobeli f\u00fc\u00fcsikapreemia, mis l\u00e4ks Manchesteri \u00dclikooli\u00a0 f\u00fc\u00fcsikutele Andre Geimile ja Konstantin Novosjolovile, kes viisid veidi rohkem kui 5 aastat tagasi l\u00e4bi murrangulised eksperimendid selle 2-dimensionaalse materjaliga (vt <a href=\"http:\/\/www.horisont.ee\/node\/1538\">Horisont 6\/2010<\/a>). Alates 2008. aastast on grafeeniga tegeldud ka Tartu \u00dclikooli F\u00fc\u00fcsika Instituudis, kus on uuritud v\u00f5imalusi, kuidas katta grafeeni keemiliselt inertne pind \u00fcli\u00f5hukese, ideaalis vaid m\u00f5ne nanomeetri paksuse ning samas pideva ja \u00fchtlase\u00a0 paksusega isolaatorkihiga, mis oleks kindlasti vajalik grafeenil p\u00f5hinevate nanoelektrooniliste seadmete valmistamiseks (vt <a href=\"http:\/\/www.horisont.ee\/node\/1266\">Horisont 6\/2009<\/a>). Nendest eksperimentidest ilmus hiljuti Tartu materjaliteadlastelt \u00fclevaateartikkel <em>&#8221;<a href=\"http:\/\/www.intechopen.com\/articles\/show\/title\/atomic-layer-deposition-of-high-k-oxides-on-graphene\">Atomic layer deposition of high-k oxides on graphene&#8221;<\/a><\/em><em> <\/em>[1], kus on \u00fcritatud anda pilt nii enda kui ka teiste uurimisr\u00fchmade saavutustest sellel alal.<\/p>\n<p>Grafeeni katmiseks \u00f5hukese isolaatorkihiga v\u00f5ib kasutada erinevaid meetodeid, kuid \u00fcks perpektiivikamaid neist on aatomkihtsadestamine (<em>ingl<\/em> Atomic Layer Deposition, ALD), millega Tartus on tegeldud juba rohkem kui paar aastak\u00fcmmet. Et saada \u00f5hukest heade dielektriliste omadustega kattekihti, kasutati kahetemperatuurset kasvatusprotsessi. N\u00e4iteks kvaliteetse\u00a0 HfO<sub>2<\/sub>-kihi jaoks s\u00fcnteesiti k\u00f5igepealt suhteliselt madalal temperatuuril (170-180<sup>o<\/sup>C) grafeeni pinnale umbes 1 nm paksune nakkekiht, mille peale k\u00f5rgemal temperatuuril (300<sup>o<\/sup>C) s\u00fcnteesiti \u00fclej\u00e4\u00e4nud dielektrikkiht paksusega 10-30 nm. Nendel tingimustel sadestus HfO<sub>2<\/sub> grafeenile sama h\u00e4sti kui r\u00e4nioksiidile (vt joonis). Nagu n\u00e4itasid v\u00f5etud Raman-spektrid, ei tekitanud selline sadestamismeetod grafeenis t\u00e4iendavaid defekte. Koost\u00f6\u00f6s Aalto \u00dclikooli K\u00fclmalaboriga uuriti ka HfO<sub>2<\/sub>-kihi m\u00f5ju grafeeni laengukandjate liikuvusele <em><a href=\"http:\/\/www.springerlink.com\/content\/q673467638192t70\/\">&#8221;Atomic layer deposition of HfO<sub>2<\/sub> on graphene from HfCl<sub>4<\/sub> and H<sub>2<\/sub>O&#8221;, <\/a>[2]<\/em>.<\/p>\n<div id=\"attachment_21734\" style=\"width: 581px\" class=\"wp-caption alignleft\"><a href=\"http:\/\/www.fyysika.ee\/uudised\/wp-content\/uploads\/2011\/10\/Alles_grafen.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-21734\" class=\"size-full wp-image-21734  \" title=\"Alles_grafen\" src=\"http:\/\/www.fyysika.ee\/uudised\/wp-content\/uploads\/2011\/10\/Alles_grafen.jpg\" alt=\"\" width=\"571\" height=\"177\" srcset=\"https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/10\/Alles_grafen.jpg 704w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/10\/Alles_grafen-300x93.jpg 300w, https:\/\/www.fyysika.ee\/wp-content\/uploads\/2011\/10\/Alles_grafen-250x77.jpg 250w\" sizes=\"auto, (max-width: 571px) 100vw, 571px\" \/><\/a><p id=\"caption-attachment-21734\" class=\"wp-caption-text\">Joonis.  Vasakul, aatomj\u00f5umikroskoobi pilt r\u00e4nidioksiidil asuva grafeenin\u00e4idise  servast. Nii grafeeni (heledam osa vasakul all) kui ka r\u00e4nidioksiidi  pind (paremal \u00fclal) on kaetud \u00fchtlase HfO2-kihiga. Paremal, grafeeni ja  r\u00e4nidioksiidi k\u00f5rguseprofiilide vahe (~0.8 nm) on j\u00e4\u00e4nud samaks ka peale  grafeeni dielektrikuga katmist kahetemperatuurses sadestusprotsessis. <\/p><\/div>\n<p>\u00dclevaate grafeeniuuringutest Tartu \u00dclikoolis kirjutas Dr.Harry Alles<\/p>\n<p>1.<em><a href=\"http:\/\/www.intechopen.com\/articles\/show\/title\/atomic-layer-deposition-of-high-k-oxides-on-graphene\"> Atomic  layer deposition of high-k oxides on graphene. Graphene \u2013 Synthesis,  Characterization, Properties and Applications, Jian Ru Gong (Ed.),  InTech, 99-114 (2011)<\/a><\/em> .<\/p>\n<p>2. <em><a href=\"http:\/\/www.springerlink.com\/content\/q673467638192t70\/\">Atomic layer deposition of HfO<sub>2<\/sub> on graphene from HfCl<sub>4<\/sub> and H<sub>2<\/sub>O, Central European Journal of Physics <strong>9<\/strong>, 319-324 (2011)<\/a><\/em>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00dcheainsa aatomikihi paksune grafeen, mille moodustavad kuusnurkses v\u00f5res olevad s\u00fcsinikuaatomid ja mida loetakse hetkel k\u00f5ige potentsiaalsemaks j\u00e4rglaseks r\u00e4nile tuleviku nanoelektroonikas, on olnud viimastel aastatel ehk enim uuritud materjal. Materjaliteaduses valitsenud \u201cgrafeenibuumile\u201d andis l\u00e4inud aastal veelgi hoogu juurde 2010. aasta Nobeli f\u00fc\u00fcsikapreemia, mis l\u00e4ks Manchesteri \u00dclikooli\u00a0 f\u00fc\u00fcsikutele Andre Geimile ja Konstantin Novosjolovile, kes viisid veidi rohkem [&hellip;]<\/p>\n","protected":false},"author":27,"featured_media":21745,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[37,107,16],"tags":[45],"class_list":{"0":"post-21733","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-eestist-endast","8":"category-tartu-ulikool","9":"category-teadusuudis","10":"tag-grafeengrafaan","11":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/21733","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/27"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=21733"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/21733\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/media\/21745"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21733"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21733"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21733"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}