{"id":55325,"date":"2023-02-03T15:47:58","date_gmt":"2023-02-03T13:47:58","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=55325"},"modified":"2023-02-03T15:47:58","modified_gmt":"2023-02-03T13:47:58","slug":"these-peric-n-densite-detats-discontinuite-de-bande-et-injection-de-charge-dans-des-nanostructures-unidimensionnelles-semi-conductrices-analysees-par-microscopie-a-effet-tunnel-a-pointes-multi","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/these\/these-2021\/these-peric-n-densite-detats-discontinuite-de-bande-et-injection-de-charge-dans-des-nanostructures-unidimensionnelles-semi-conductrices-analysees-par-microscopie-a-effet-tunnel-a-pointes-multi.html","title":{"rendered":"THESIS: PERIC N. - Density of states, band discontinuity and charge injection in one-dimensional semiconductor nanostructures analysed by multipoint scanning tunneling microscopy."},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_heading  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_58_uyot88bv04no\" data-ls-slug=\"homepageslider\" class=\"ls-wp-container fitvidsignore ls-selectable\" style=\"width:1140px;height:260px;margin:0 auto;margin-bottom: 0px;\"><div class=\"ls-slide\" data-ls=\"duration:6000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-705x73.jpg 705w\" sizes=\"auto, (max-width: 2600px) 100vw, 2600px\" \/><ls-layer style=\"font-size:14px;text-align:left;font-style:normal;text-decoration:none;text-transform:none;font-weight:700;letter-spacing:0px;border-style:solid;border-color:#000;background-position:0% 0%;background-repeat:no-repeat;width:180px;height:30px;left:0px;top:231px;line-height:32px;color:#ffffff;border-radius:6px 6px 6px 6px;padding-left:50px;background-color:rgba(0, 0, 0, 0.57);\" class=\"ls-l ls-ib-icon ls-text-layer\" data-ls=\"minfontsize:0;minmobilefontsize:0;\"><i class=\"fa fa-quote-right\" style=\"color:#ffffff;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>ACTUALITES<\/ls-layer><\/div><\/div><\/div><div id='after_layer_slider_1'  class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-55325'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-lawku1k0-c4305d8a1dc9d7b441c336dfcdb3b440\">\n#top .av-special-heading.av-lawku1k0-c4305d8a1dc9d7b441c336dfcdb3b440{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-lawku1k0-c4305d8a1dc9d7b441c336dfcdb3b440 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-lawku1k0-c4305d8a1dc9d7b441c336dfcdb3b440 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-lawku1k0-c4305d8a1dc9d7b441c336dfcdb3b440 av-special-heading-h2  avia-builder-el-1  el_after_av_layerslider  el_before_av_hr  avia-builder-el-first'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >THESE : PERIC N. &#8211; Densit\u00e9 d\u2019\u00e9tats, discontinuit\u00e9 de bande et injection de charge dans des nanostructures unidimensionnelles semi-conductrices analys\u00e9es par microscopie \u00e0 effet tunnel \u00e0 pointes multiples <\/h2><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-18u73nj-dad6a947580930e400fc42ba200e80f1\">\n#top .hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1{\nmargin-top:5px;\nmargin-bottom:5px;\n}\n.hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1 .hr-inner{\nwidth:100%;\n}\n<\/style>\n<div  class='hr av-18u73nj-dad6a947580930e400fc42ba200e80f1 hr-custom  avia-builder-el-2  el_after_av_heading  el_before_av_textblock  hr-left hr-icon-no'><span class='hr-inner inner-border-av-border-thin'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<section  class='av_textblock_section av-jriy64i8-2f4600354c0449b610997916bbd9b6bc'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" >\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-13ewzjw-68e036126b913e5028f77311dc66b825\">\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825{\ncolor:#bfbfbf;\nborder-color:#bfbfbf;\n}\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825 .av-icon-char{\nfont-size:60px;\nline-height:60px;\n}\n<\/style>\n<span  class='av_font_icon av-13ewzjw-68e036126b913e5028f77311dc66b825 avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue8c9' data-av_iconfont='entypo-fontello' ><\/span><\/span>\n<p><strong>PERIC N.<br \/>\n<\/strong><\/p>\n<p>Soutenance : 27 Janvier 2021<strong><br \/>\n<\/strong>Th\u00e8se de doctorat en Electronique, micro\u00e9lectronique, nano\u00e9lectronique et micro-ondes, Universit\u00e9 de Lille.<br \/>\nAssociated project: RENATECH<\/p>\n<\/div><\/section>\n<section  class='av_textblock_section av-jtefqx33-628129dba2299b2ecd65ebfc92eac29d'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div  class='hr av-kjh3zw-4dff888f744b728a1aca9b3a0971493a hr-default  avia-builder-el-6  avia-builder-el-no-sibling'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<h5>Summary:<\/h5>\n<p>La miniaturisation continue des composants \u00e9lectroniques a atteint un seuil au-del\u00e0 duquel les effets quantiques deviendront pr\u00e9pond\u00e9rants. Plut\u00f4t que de vouloir supprimer ces effets, il peut \u00eatre int\u00e9ressant de les mettre \u00e0 profit. Mais ce changement de perspective n\u00e9cessite d\u2019avoir une compr\u00e9hension plus fine des propri\u00e9t\u00e9s \u00e9lectroniques de nanostructures semi-conductrices consid\u00e9r\u00e9es comme de potentiels \u00e9l\u00e9ments actifs dans des dispositifs futurs. Au cours de cette th\u00e8se, deux types de structures dont la g\u00e9om\u00e9trie s\u2019apparente plus ou moins \u00e0 un syst\u00e8me uni-dimensionnel ont \u00e9t\u00e9 consid\u00e9r\u00e9s: des nanofils semi-conducteurs III-V fabriqu\u00e9s par croissance \u00e9pitaxiale en ultravide et des nanoplatelets semi-conducteurs II-VI synth\u00e9tis\u00e9s chimiquement. Dans le premier cas, l\u2019\u00e9pitaxie par jets mol\u00e9culaires s\u00e9lective de nanofils planaires compos\u00e9s d\u2019InGaAs permet d\u2019\u00e9laborer des nano-cristaux localis\u00e9s pr\u00e9cis\u00e9ment \u00e0 la surface d\u2019un substrat d\u2019InP gr\u00e2ce \u00e0 l\u2019utilisation d\u2019un masque di\u00e9lectrique. L\u2019analyse de la morphologie de ces nanofils par microscopie \u00e0 champ proche a r\u00e9v\u00e9l\u00e9 une anisotropie de forme en fonction de l\u2019orientation des nanofils. En mod\u00e9lisant la cin\u00e9tique de croissance, nous avons montr\u00e9 que cette variation de forme s\u2019explique par une diff\u00e9rence de diffusion des adatomes li\u00e9e \u00e0 la reconstruction (2&#215;4) de la surface (001) des nanofils. Les propri\u00e9t\u00e9s de transport dans ces h\u00e9t\u00e9rostructures uni-dimensionelles In0.53Ga0.46As\/InP ont ensuite \u00e9t\u00e9 caract\u00e9ris\u00e9es par microscopie \u00e0 effet tunnel \u00e0 pointes multiples. Deux approches exp\u00e9rimentales bas\u00e9es l\u2019une sur la spectroscopie tunnel \u00e0 deux contacts, l\u2019autre sur des mesures \u00e0 quatre pointes en contact ont \u00e9t\u00e9 con\u00e7ues pour remonter \u00e0 la mesure des discontinuit\u00e9s de bande entre le substrat d\u2019InP et les nanofils d\u2019InGaAs. L\u2019obtention des discontinuit\u00e9s de bande est directe et ne requiert ni fabrication d\u2019\u00e9lectrodes, ni mod\u00e9lisation des caract\u00e9ristiques I(V), contrairement aux techniques \u00e9lectriques conventionnelles. Dans un second temps, nous avons consid\u00e9r\u00e9 des nanoplaquettes de CdSe, qui s\u2019apparentent \u00e0 des puits quantiques collo\u00efdaux d\u2019\u00e9paisseur limit\u00e9e \u00e0 quelques plans atomiques pour des dimensions lat\u00e9rales comprises entre plusieurs nanom\u00e8tres et quelques dizaines de nanom\u00e8tres. Bien que les propri\u00e9t\u00e9s excitoniques des nanoplaquettes aient fait l\u2019objet de nombreuses \u00e9tudes, le r\u00f4le du confinement quantique lat\u00e9rale sur la localisation des porteurs de charge est encore mal connu. En utilisant la microscopie \u00e0 effet tunnel, nous avons caract\u00e9ris\u00e9 des nanoplaquettes individuelles et des nanoplaquettes assembl\u00e9es en paquet pour d\u00e9terminer la densit\u00e9 d\u2019\u00e9tats en bande de conduction. Les mesures spectroscopiques montrent l\u2019existence, d\u2019une part, de singularit\u00e9s superpos\u00e9es \u00e0 une oscillation de la densit\u00e9 d\u2019\u00e9tats, en bon accord avec la densit\u00e9 d\u2019\u00e9tats calcul\u00e9e par la m\u00e9thode des liaisons fortes et, d\u2019autre part, la pr\u00e9sence de pi\u00e8ge sur les parois lat\u00e9rales des plaquettes. Contrairement \u00e0 l\u2019exciton dont le confinement est plus important, la d\u00e9localisation de l\u2019\u00e9lectron est fortement influenc\u00e9e par le confinement lat\u00e9ral et la pr\u00e9sence de pi\u00e8ge. A cet effet, des travaux pr\u00e9liminaires par spectroscopie optique de nanoplaquettes coeur-coquille permet d\u2019entrevoir l\u2019int\u00e9r\u00eat d\u2019une couronne pour mieux contr\u00f4ler le confinement des porteurs de charge dans ces objets.<\/p>\n<h5>Abstract:<\/h5>\n<p>The continuous miniaturization of electronic components has reached a threshold beyond which quantum effects will become preponderant. Rather than trying to suppress these effects, it may be interesting to take advantage of them. But this change of perspective requires a more detailed understanding of the electronic properties of semiconductor nanostructures considered as potential active elements in future devices. During this thesis, two types of structures whose geometry is more or less similar to a one-dimensional system have been considered: III-V semiconductor nanowires fabricated by epitaxial growth in ultra-high vacuum and chemically synthesized II-VI semiconductor nanoplatelets. In the first case, selective molecular beam epitaxy of planar nanowires composed of InGaAs allows to grow precisely localized nanocrystals on the surface of an InP substrate through the use of a dielectric mask. The analysis of the morphology of these nanowires by near-field microscopy revealed a shape anisotropy depending on the orientation of the nanowires. By modeling the growth kinetics, we showed that this shape variation is explained by a difference in adatom diffusion related to the (2&#215;4) reconstruction of the (001) nanowire surface. The transport properties in these one-dimensional In0.53Ga0.46As\/InP heterostructures were then characterized by multipoint scanning tunneling microscopy. Two experimental approaches based on two-contact tunneling spectroscopy and four-point contact measurements were designed to trace the band discontinuities between the InP substrate and the InGaAs nanowires. Obtaining the band discontinuities is direct and does not require either electrode fabrication or modeling of I(V) characteristics, unlike conventional electrical techniques. In a second step, we considered CdSe nanoplatelets, which are similar to colloidal quantum wells with thickness limited to a few atomic planes for lateral dimensions ranging from several nanometers to a few tens of nanometers. Although the excitonic properties of nanoplatelets have been extensively studied, the role of lateral quantum confinement on charge carrier localization is still poorly understood. Using scanning tunneling microscopy, we have characterized individual nanoplatelets and nanoplatelets assembled in a bundle to determine the density of states in the conduction band. The spectroscopic measurements show the existence of singularities superimposed on an oscillation of the density of states, in good agreement with the density of states calculated by the strong bond method, and the presence of traps on the sidewalls of the platelets. Contrary to the exciton whose confinement is more important, the electron delocalization is strongly influenced by the lateral confinement and the presence of traps. To this end, preliminary work by optical spectroscopy of core-shell nanoplatelets allows to foresee the interest of a corona to better control the confinement of charge carriers in these objects.<\/p>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":20,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[317],"tags":[],"class_list":["post-55325","post","type-post","status-publish","format-standard","hentry","category-these-2021"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/55325","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=55325"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/55325\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=55325"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=55325"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=55325"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}