{"id":57031,"date":"2023-03-28T08:41:52","date_gmt":"2023-03-28T06:41:52","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=57031"},"modified":"2023-03-28T08:55:21","modified_gmt":"2023-03-28T06:55:21","slug":"57031","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/actualites\/57031.html","title":{"rendered":"S\u00e9minaire de St\u00e9phane BERCIAUD \u2013 Optical spectroscopy and nanoscopy in 2D semiconductor\/graphene van der  Waals heterostructures"},"content":{"rendered":"<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-1p4ar7r-43109accd7d777d50db24b4d127029b8\">\n.flex_column.av-1p4ar7r-43109accd7d777d50db24b4d127029b8{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-1p4ar7r-43109accd7d777d50db24b4d127029b8 av_one_full  avia-builder-el-0  el_before_av_one_half  avia-builder-el-first  first flex_column_div av-zero-column-padding'     ><section  class='av_textblock_section av-lfrw2xqi-8210d1c1817c434b9a2a415ac4bf908e'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><h2 style=\"text-align: center;\">Seminar<\/h2>\n<hr \/>\n<blockquote>\n<p>Tuesday, April 4, 2023 at 2:00 PM - Salle du Conseil du LCI<br \/>\nSeminar presented by <strong>St\u00e9phane BERCIAUD<\/strong>,<br \/>\nUniversity of Strasbourg, CNRS, IPCMS (UMR 7504), Strasbourg, France<\/p>\n<p><strong>\"\u00a0<\/strong><strong>Optical spectroscopy and nanoscopy in 2D semiconductor\/graphene van der\u00a0Waals heterostructures\u00a0\u00bb<\/strong><br \/>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-wzsvks-2a4e30804f9db3ceeeeb0ecf79e8d718\">\n.av_font_icon.av-wzsvks-2a4e30804f9db3ceeeeb0ecf79e8d718{\ncolor:#7bb0e7;\nborder-color:#7bb0e7;\n}\n.av_font_icon.av-wzsvks-2a4e30804f9db3ceeeeb0ecf79e8d718 .av-icon-char{\nfont-size:25px;\nline-height:25px;\n}\n<\/style>\n<span  class='av_font_icon av-wzsvks-2a4e30804f9db3ceeeeb0ecf79e8d718 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='\ue826' data-av_iconfont='entypo-fontello' ><\/span><\/span><a href=\"https:\/\/fcbg.team\/\" target=\"_blank\" rel=\"noopener\">Read more<\/a><\/p>\n<\/blockquote>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-1bq3sdj-902bfe575967a4b659a90d9e173fc6ad\">\n.flex_column.av-1bq3sdj-902bfe575967a4b659a90d9e173fc6ad{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-1bq3sdj-902bfe575967a4b659a90d9e173fc6ad av_one_half  avia-builder-el-3  el_after_av_one_full  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lfrw3s6e-85a3b42a3fedf2f82b8832fadc8f68be'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>The broad palette of two dimensional (2D) materials and the \u201ctwist\u201d<br \/>\ndegree of freedom between 2D layers offer countless possibilities to<br \/>\nconceive and assemble van der Waals (vdW) heterostructures. The physics<br \/>\nof such artificial materials and their performance as emergent<br \/>\n(opto-)electronic, and photonic devices is governed by interfacial<br \/>\ncoupling through, interlayer charge and\/or energy transfer as well as<br \/>\ndielectric screening. At the same time, materials-related issues, such<br \/>\nas micro- and nano-scale dielectric disorder, strain gradients,<br \/>\nunintentional doping, atomic reconstruction, \/etc\/. have a major impact<br \/>\non the physics of vdW heterostructures. It is therefore essential to<br \/>\nprobe vdW heterostructures in- and out-of-plane at the nano- and even<br \/>\natomic scale. This seminar will describe two complementary efforts in<br \/>\nthis direction, with a focus on the optical properties of<br \/>\nheterojunctions made from 2D semiconductors (here, transition metal<br \/>\ndichalcogenide (TMD) monolayers) coupled to graphene.<\/p>\n<p>In a first part, we will exploit van der Waals engineering and<br \/>\ndiffraction-limited optical spectroscopy to precisely probe interfacial<br \/>\ncoupling between TMD monlayers and graphene separated only by a<br \/>\nsub-nanometer vdW gap [1]. We will show how graphene alters the dynamics<br \/>\nand radiative recombination of excitons (bound electron-hole pairs) in<br \/>\nTMDs, leading to a remarkable \u201cfiltering effect\u201d (Fig. 1 and [2]) and,<br \/>\ncomplementarily, how the optical phonons in graphene provide invaluable<br \/>\ninsights into dielectric screening and interfacial coupling in<br \/>\ngraphene-based vdW heterostructures [3].<\/p>\n<\/div><\/section><\/div><\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-34i06f-5ab042f242ea486accbf1a9b775d56c0\">\n.flex_column.av-34i06f-5ab042f242ea486accbf1a9b775d56c0{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-34i06f-5ab042f242ea486accbf1a9b775d56c0 av_one_half  avia-builder-el-5  el_after_av_one_half  avia-builder-el-last  flex_column_div av-zero-column-padding  column-top-margin'     ><section  class='av_textblock_section av-lfrw3s6e-85a3b42a3fedf2f82b8832fadc8f68be'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><p>In a second part, we will show that a low-temperature scanning tunneling<br \/>\nmicroscope (STM) can probe, with atomic-scale spatial resolution, the<br \/>\nexcitonic luminescence of a vdW heterostructure, made of a TMD monolayer<br \/>\nstacked onto a graphene flake [4]. This work paves the way towards<br \/>\nunderstanding and control of individual quantum emitters and more<br \/>\nbroadly of optoelectronic phenomena in moir\u00e9 superlattices with<br \/>\natomic-scale resolution.<\/p>\n<p>This was work done within the Nano-Optics and Low-Dimensional Materials<br \/>\nteam &lt;<a class=\"zUrl\" href=\"https:\/\/fcbg.team\/\" target=\"_blank\" rel=\"noopener\">https:\/\/fcbg.team\/<\/a>&gt;at IPCMS, in collaboration with the STM team at<br \/>\nIPCMS (G. Schull \/et al.\/) and the LPCNO at INSA Toulouse (C. Robert, D.<br \/>\nLagarde, X. Marie).<\/p>\n<p><strong><span style=\"color: #800000;\">References:<\/span><\/strong><\/p>\n<p><em>[1] G. Froehlicher, E. Lorchat, S. Berciaud, Phys. Rev. X *8,* 011007 (2018)<\/em><\/p>\n<p><em>[2] E. Lorchat, L. E. Parra L\u00f3pez \/et al.\/, Nature Nanotechnology. *15*,<\/em><br \/>\n<em> 283 (2020) -arXiv:1908.10690 &lt;<a class=\"zUrl\" href=\"https:\/\/arxiv.org\/abs\/1908.10690\" target=\"_blank\" rel=\"noopener\">https:\/\/arxiv.org\/abs\/1908.10690<\/a>&gt;<\/em><\/p>\n<p><em>[3] L. Moczko \/et al.\/, submitted (2022)<\/em><\/p>\n<p><em>[4] L. E. Parra L\u00f3pez \/et al.\/, Nature Materials (in press, 2023)<\/em><br \/>\n<em> -\/\/\/<a class=\"zUrl\" href=\"https:\/\/doi.org\/10.1038\/s41563-023-01494-4\" target=\"_blank\" rel=\"noopener\">https:\/\/doi.org\/10.1038\/s41563-023-01494-4<\/a>\u00a0\/arXiv:2204.14022<\/em><br \/>\n<em> &lt;<a class=\"zUrl\" href=\"https:\/\/arxiv.org\/abs\/2204.14022\" target=\"_blank\" rel=\"noopener\">https:\/\/arxiv.org\/abs\/2204.14022<\/a>&gt;<\/em><\/p>\n<div  class='avia-button-wrap av-rpqvoq-8addaf6ece4f69e798b159296216a9d5-wrap avia-button-left  avia-builder-el-7  avia-builder-el-no-sibling'><a href='mailto:maxime.berthe@univ-lille.fr'  class='avia-button av-rpqvoq-8addaf6ece4f69e798b159296216a9d5 av-link-btn avia-icon_select-yes-left-icon avia-size-small avia-position-left avia-color-silver'   aria-label=\"maxime.berthe@univ-lille.fr\"><span class='avia_button_icon avia_button_icon_left' aria-hidden='true' data-av_icon='\ue805' data-av_iconfont='entypo-fontello'><\/span><span class='avia_iconbox_title' >maxime.berthe@univ-lille.fr<\/span><\/a><\/div>\n<\/div><\/section><\/div>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":57039,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,65],"tags":[],"class_list":["post-57031","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-actualites","category-agenda"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/57031","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\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=57031"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/57031\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media\/57039"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=57031"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=57031"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=57031"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}