{"id":24875,"date":"2018-09-20T12:10:04","date_gmt":"2018-09-20T10:10:04","guid":{"rendered":"https:\/\/www.iemn.fr\/?page_id=24875"},"modified":"2024-07-08T09:31:18","modified_gmt":"2024-07-08T07:31:18","slug":"on-going-studies","status":"publish","type":"page","link":"https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes\/epiphy\/on-going-studies","title":{"rendered":"On-going studies"},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_submenu  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_17_1b86emypr3uml\" 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=\"bgposition:50% 50%;duration:6000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy_four1-705x73.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;background-position:0% 0%;background-repeat:no-repeat;mix-blend-mode:normal;top:231px;left:0px;height:30px;width:320px;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-user-circle\" style=\"color:#f2f2f2;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>GROUPE DE RECHERCHE : EPIPHY<\/ls-layer><\/div><div class=\"ls-slide\" data-ls=\"duration:4000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/04\/sliders_epiphy.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/04\/sliders_epiphy.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/04\/sliders_epiphy-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/04\/sliders_epiphy-768x80.jpg 768w, 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data-ls=\"duration:4000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2017\/04\/sliders_page-daccueil1_7.gif\" class=\"ls-bg\" alt=\"\" \/><ls-layer style=\"font-size:14px;text-align:left;font-style:normal;text-decoration:none;text-transform:none;font-weight:700;letter-spacing:0px;background-position:0% 0%;background-repeat:no-repeat;mix-blend-mode:normal;top:231px;left:0px;height:30px;width:320px;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-user-circle\" style=\"color:#f2f2f2;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>GROUPE DE RECHERCHE : EPIPHY<\/ls-layer><\/div><div class=\"ls-slide\" data-ls=\"duration:4000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/sliders_groupe_epiphy4-2-705x73.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;background-position:0% 0%;background-repeat:no-repeat;mix-blend-mode:normal;top:231px;left:0px;height:30px;width:320px;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-user-circle\" style=\"color:#f2f2f2;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>GROUPE DE RECHERCHE : EPIPHY<\/ls-layer><\/div><\/div><\/div>\n<div id='sub_menu1'  class='av-submenu-container av-jrqfadqy-ce2f2ab09b07c9cd48b0b2cdd423b7d9 footer_color  avia-builder-el-1  el_after_av_layerslider  el_before_av_heading  submenu-not-first container_wrap sidebar_right' style='z-index:301' ><div class='container av-menu-mobile-disabled av-submenu-pos-left'><ul id='av-custom-submenu-1' class='av-subnav-menu' role='menu'>\n<li class='menu-item av-3r1s3yj-67e5c33968b28b30122b437811629164 menu-item-top-level menu-item-top-level-1' role='menuitem'><a href='https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes\/epiphy'  ><span class='avia-bullet'><\/span><span class='avia-menu-text'>Introduction<\/span><\/a><\/li>\n<li class='menu-item av-3nhu223-1e929a91d82ce0f963bce5e455882ddd menu-item-top-level menu-item-top-level-2' role='menuitem'><a href='https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes\/epiphy\/members'  ><span class='avia-bullet'><\/span><span class='avia-menu-text'>Team members<\/span><\/a><\/li>\n<li class='menu-item av-33h94ln-081428d7d3762caf6c9a485eb0fed9d9 menu-item-top-level menu-item-top-level-3' role='menuitem'><a href='https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes\/epiphy\/masters-phds'  ><span class='avia-bullet'><\/span><span class='avia-menu-text'>Masters - PhDs<\/span><\/a><\/li>\n<li class='menu-item av-900mln-a0cbe068ffe9eadf3c4c49849a999b4a menu-item-top-level menu-item-top-level-4' role='menuitem'><a href='https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes\/epiphy\/equipment'  ><span class='avia-bullet'><\/span><span class='avia-menu-text'>Equipment<\/span><\/a><\/li>\n<li class='menu-item av-28jb3rf-02568fc55eca65ca7a497d065b51066e menu-item-top-level menu-item-top-level-5' role='menuitem'><a href='https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes\/epiphy\/on-going-studies'  ><span class='avia-bullet'><\/span><span class='avia-menu-text'>On-going studies<\/span><\/a><\/li>\n<li class='menu-item av-1bmt7qj-d12f3296084cba81ca2886d85c09d585 menu-item-top-level menu-item-top-level-6' role='menuitem'><a href='https:\/\/www.iemn.fr\/en\/la-recherche\/les-groupes'  ><span class='avia-bullet'><\/span><span class='avia-menu-text'>Other groups<\/span><\/a><\/li>\n<\/ul><\/div><\/div><div id='after_submenu_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-24875'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4cathn-7cabf0ff26dcaf679c14c553212c1e1c\">\n#top .av-special-heading.av-4cathn-7cabf0ff26dcaf679c14c553212c1e1c{\npadding-bottom:10px;\n}\nbody .av-special-heading.av-4cathn-7cabf0ff26dcaf679c14c553212c1e1c .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-4cathn-7cabf0ff26dcaf679c14c553212c1e1c .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-4cathn-7cabf0ff26dcaf679c14c553212c1e1c av-special-heading-h2  avia-builder-el-2  el_after_av_submenu  el_before_av_one_full  avia-builder-el-first'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >EPIPHY Group : On-going studies<\/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-ytik8b-9dedccb14533c641dc5f21d7a677995e\">\n.flex_column.av-ytik8b-9dedccb14533c641dc5f21d7a677995e{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div  class='flex_column av-ytik8b-9dedccb14533c641dc5f21d7a677995e av_one_full  avia-builder-el-3  el_after_av_heading  avia-builder-el-last  first flex_column_div av-zero-column-padding'     ><div  class='togglecontainer av-jmaf3dmh-d27cb37bcad28f5566625102aeaea1dc  avia-builder-el-4  avia-builder-el-no-sibling  toggle_close_all' >\n<section class='av_toggle_section av-t06jxn-ac085d0677dea49920fdd46415473cd7'  itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\" ><div role=\"tablist\" class=\"single_toggle\" data-tags=\"{All} \"  ><p id='toggle-toggle-id-1' data-fake-id='#toggle-id-1' class='toggler  av-title-above'  itemprop=\"headline\"  role='tab' tabindex='0' aria-controls='toggle-id-1' data-slide-speed=\"200\" data-title=\"Selective area Molecular Beam Epitaxy of III-V nanostructures\" data-title-open=\"\" data-aria_collapsed=\"Click to expand: Selective area Molecular Beam Epitaxy of III-V nanostructures\" data-aria_expanded=\"Click to collapse: Selective area Molecular Beam Epitaxy of III-V nanostructures\">Selective area Molecular Beam Epitaxy of III-V nanostructures<span class=\"toggle_icon\"><span class=\"vert_icon\"><\/span><span class=\"hor_icon\"><\/span><\/span><\/p><div id='toggle-id-1' aria-labelledby='toggle-toggle-id-1' role='region' class='toggle_wrap  av-title-above'  ><div class='toggle_content invers-color'  itemprop=\"text\" ><p>Low electron effective mass materials such as In(Ga)As or InSb exhibit very interesting properties for different type of applications : high frequency\/low power electronic devices (thanks to their low electron effective mass), infrared optoelectronics (thanks to their small bandgap) or quantum technologies (thanks to their large spin-orbit coupling). However, these materials also exhibit a large lattice mismatch with standard semiconducting substrates (Si, GaAs).<\/p>\n<p>After several studies concerning strain relaxation mechanisms in highly mismatched systems and development of solution to reduce the impact of plastic deformation on the electronic properties of III-V semiconductors, we are investigating now the possibility of growing selectively these materials at the nanoscale. This approach has several advantages:<\/p>\n<ul>\n<li>promotion of the mismatch accommodation by confining the plastic deformation area at the interface with the substrate.<\/li>\n<li>reduction of the effect of different thermal expansion coefficients between the layer and the substrate.<\/li>\n<li>elaboration of nanostructures by a bottom-up way, thus avoiding surface degradation induced by dry etching.<\/li>\n<\/ul>\n<p>If MOCVD is the most currently used technique for selective area epitaxy (thanks to the catalytic decomposition of precursors inside the mask aperture), Molecular Beam Epitaxy can also be used by adjusting carefully the growth parameters (growth rate, temperature, flux ratio) in order to promote the re-evaporation of III-elements from the dielectric mask. We have demonstrated that the use of an atomic hydrogen flux during the growth improves the selectivity for materials containing gallium or indium. Figure 1 shows the effect of an atomic hydrogen flux during the growth of GaSb on GaAs at 470\u00b0C.<\/p>\n<div id=\"attachment_25477\" style=\"width: 810px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular_atomic-2.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-25477\" class=\"wp-image-25477 size-full\" title=\"Figure 1 : Growth of 65 nm GaSb on a GaAs susbtrate covered with a SiO2 mask, without (left) and with (right) atomic hydrogen flux during MBE [M. Fahed et al, Nanotechnology 27, 50 (2016)]\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular_atomic-2.jpg\" alt=\"Figure 1 : Growth of 65 nm GaSb on a GaAs susbtrate covered with a SiO2 mask, without (left) and with (right) atomic hydrogen flux during MBE [M. Fahed et al, Nanotechnology 27, 50 (2016)]\" width=\"800\" height=\"265\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular_atomic-2.jpg 800w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular_atomic-2-300x99.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular_atomic-2-768x254.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular_atomic-2-705x234.jpg 705w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/a><p id=\"caption-attachment-25477\" class=\"wp-caption-text\">Figure 1 : Growth of 65 nm GaSb on a GaAs susbtrate covered with a SiO2 mask, without (left) and with (right) atomic hydrogen flux during MBE [M. Fahed et al, Nanotechnology 27, 50 (2016)]<\/p><\/div>\n<p style=\"text-align: center\"><em>\u00a0<\/em><\/p>\n<p>This technique allows the growth of nanostructures of different III-V compound such as InAs, InGaAs, GaAs or InSb, particularly in-plane nanowires or arrays of interconnected nanowires as illustrated on figure 2. As the position of the nanostructures is well-controlled by the design of the dielectric mask, the devices can be processed easily without any transfer to a host substrate.<\/p>\n<div id=\"attachment_24897\" style=\"width: 575px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular-2.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24897\" class=\"wp-image-24897 size-full\" title=\"Figure 2 : Selective area epitaxy of an array of in plane InAs nanowires separated by GaAs nano-disks (top and bird view)\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular-2.jpg\" alt=\"Figure 2 : Selective area epitaxy of an array of in plane InAs nanowires separated by GaAs nano-disks (top and bird view)\" width=\"565\" height=\"213\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular-2.jpg 565w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/selective_area_molecular-2-300x113.jpg 300w\" sizes=\"auto, (max-width: 565px) 100vw, 565px\" \/><\/a><p id=\"caption-attachment-24897\" class=\"wp-caption-text\">Figure 2 : Selective area epitaxy of an array of in plane InAs nanowires separated by GaAs nano-disks (top and bird view)<\/p><\/div>\n<p>This approach paves the way towards the fabrication of new generation of in-plane nanowire based MOSFET, nano-tunnel diodes or ballistic nano-devices for quantum computation.<\/p>\n<\/div><\/div><\/div><\/section>\n<section class='av_toggle_section av-jvcuiz-f619971f4a10dea4170396f63adc98cc'  itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\" ><div role=\"tablist\" class=\"single_toggle\" data-tags=\"{All} \"  ><p id='toggle-toggle-id-2' data-fake-id='#toggle-id-2' class='toggler  av-title-above'  itemprop=\"headline\"  role='tab' tabindex='0' aria-controls='toggle-id-2' data-slide-speed=\"200\" data-title=\"III-V heterostructures for HEMT, TFET and advanced mesoscopic nanodevices\" data-title-open=\"\" data-aria_collapsed=\"Click to expand: III-V heterostructures for HEMT, TFET and advanced mesoscopic nanodevices\" data-aria_expanded=\"Click to collapse: III-V heterostructures for HEMT, TFET and advanced mesoscopic nanodevices\">III-V heterostructures for HEMT, TFET and advanced mesoscopic nanodevices<span class=\"toggle_icon\"><span class=\"vert_icon\"><\/span><span class=\"hor_icon\"><\/span><\/span><\/p><div id='toggle-id-2' aria-labelledby='toggle-toggle-id-2' role='region' class='toggle_wrap  av-title-above'  ><div class='toggle_content invers-color'  itemprop=\"text\" ><p>The fabrication of III-V Field Effect Transistors, key components for electronic circuits working in the submillimeter wave range, relies on the epitaxy of heterostructures with an In(Ga)As channel associated either with AlInAs barriers or with an oxide. In this context, composite InGaAs\/InAs channel has been developed for the fabrication of III-V MOSFETs during the <strong>MOSInAs ANR project<\/strong> (ANR-13-NANO-0001-01; coordinator: Sylvain Bollaert, IEMN; partners : LETI, LTM, IMEP, IEF, STM). Finally, InGaAs is also the material of choice as absorbing layer in uni-travelling carrier photodiodes (UTC-PD), pushing the cut-off frequencies of photodetection towards the THz frequencies (Figure 1).<\/p>\n<p><div id=\"attachment_24903\" style=\"width: 1101px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24903\" class=\"wp-image-24903 size-full\" title=\"Figure 1: Schematic of the UTC device and SEM image of UTC-PD integrated with CPW [P. Latzel et al , IEEE Transactions on Terahertz Science and Technology 7, 800 (2017)]\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1.jpg\" alt=\"Figure 1: Schematic of the UTC device and SEM image of UTC-PD integrated with CPW [P. Latzel et al , IEEE Transactions on Terahertz Science and Technology 7, 800 (2017)]\" width=\"1091\" height=\"366\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1.jpg 1091w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1-300x101.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1-768x258.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1-1030x346.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures1-705x237.jpg 705w\" sizes=\"auto, (max-width: 1091px) 100vw, 1091px\" \/><\/a><p id=\"caption-attachment-24903\" class=\"wp-caption-text\">Figure 1: Schematic of the UTC device and SEM image of UTC-PD integrated with CPW [P. Latzel et al , IEEE Transactions on Terahertz Science and Technology 7, 800 (2017)]<\/p><\/div>The AlGaSb\/InAs system is also very suitable to obtain two-dimensional electron gas (2DEG) with an exceptional electron mobility exceeding 30 000cm<sup>2<\/sup>\/V.s at room temperature. Our previous works on strain relaxation in Sb-based materials have demonstrated a state of the art electron mobility in this system grown on GaAs substrate reaching 600 000 cm<sup>2<\/sup>\/V.s at 2K (Figure 2).<\/p>\n<div id=\"attachment_24908\" style=\"width: 549px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures3.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24908\" class=\"wp-image-24908 size-full\" title=\"Figure 2: Structural and electronic properties of IEMN AlGaSb\/InAs heterostructure grown on GaAs substrate\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures3.png\" alt=\"Figure 2: Structural and electronic properties of IEMN AlGaSb\/InAs heterostructure grown on GaAs substrate\" width=\"539\" height=\"379\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures3.png 539w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures3-300x211.png 300w\" sizes=\"auto, (max-width: 539px) 100vw, 539px\" \/><\/a><p id=\"caption-attachment-24908\" class=\"wp-caption-text\">Figure 2: Structural and electronic properties of IEMN AlGaSb\/InAs heterostructure grown on GaAs substrate<\/p><\/div>\n<p>More than the high electron mobility, the wide variety of band alignments that can be achieved in the InGaAs\/GaAsSb or AlGaSb\/InAs systems offers many opportunities for electronic and optoelectronic devices. For instance, \"Broken gap\" or \"near broken gap\" heterostructures that can be obtained varying the Al content in AlGaSb\/InAs heterostructure has been used for the fabrication of vertical tunnel FET with very high current density within the framework of the <strong>Samba ANR project<\/strong> (figure 3) (ANR 12 SAMBA JS0300801)<\/p>\n<p><div id=\"attachment_24906\" style=\"width: 1125px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24906\" class=\"wp-image-24906 size-full\" title=\"Figure 3: Vertical InAs\/AlGaSb based Tunnel FET fabricated in the frame of the ANR JCJC SAMBA project and associated transfer characteristics [V. Chinni et al, J. Electron Device Soc. 5, 53 (2017) ].\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2.jpg\" alt=\"Figure 3: Vertical InAs\/AlGaSb based Tunnel FET fabricated in the frame of the ANR JCJC SAMBA project and associated transfer characteristics [V. Chinni et al, J. Electron Device Soc. 5, 53 (2017) ].\" width=\"1115\" height=\"311\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2.jpg 1115w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2-300x84.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2-768x214.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2-1030x287.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/heterostructures2-705x197.jpg 705w\" sizes=\"auto, (max-width: 1115px) 100vw, 1115px\" \/><\/a><p id=\"caption-attachment-24906\" class=\"wp-caption-text\">Figure 3: Vertical InAs\/AlGaSb based Tunnel FET fabricated in the frame of the ANR JCJC SAMBA project and associated transfer characteristics [V. Chinni et al, J. Electron Device Soc. 5, 53 (2017) ].<\/p><\/div>Moreover, the coupling between electrons and holes at the broken gap interface between InAs and GaSb quantum wells induced a hybridization of the band structure leading to the formation of a 2D topological insulator. In the frame of <strong>TOPONANO ANR OH Risque project<\/strong> (ANR-14-OHRI-0017-03; coordinator: Silvano De Franceschi, CEA INAC; partners: IN NEL, IEMN), nanoscale devices based on this concept are studied.<\/p>\n<\/div><\/div><\/div><\/section>\n<section class='av_toggle_section av-pdwwrv-15d3267f205b3dccacdffea8704dcd12'  itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\" ><div role=\"tablist\" class=\"single_toggle\" data-tags=\"{All} \"  ><p id='toggle-toggle-id-3' data-fake-id='#toggle-id-3' class='toggler  av-title-above'  itemprop=\"headline\"  role='tab' tabindex='0' aria-controls='toggle-id-3' data-slide-speed=\"200\" data-title=\"Graphene on SiC studies\" data-title-open=\"\" data-aria_collapsed=\"Click to expand: Graphene on SiC studies\" data-aria_expanded=\"Click to collapse: Graphene on SiC studies\">Graphene on SiC studies<span class=\"toggle_icon\"><span class=\"vert_icon\"><\/span><span class=\"hor_icon\"><\/span><\/span><\/p><div id='toggle-id-3' aria-labelledby='toggle-toggle-id-3' role='region' class='toggle_wrap  av-title-above'  ><div class='toggle_content invers-color'  itemprop=\"text\" ><div id=\"attachment_24913\" style=\"width: 390px\" class=\"wp-caption alignright\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy1.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24913\" class=\"wp-image-24913 size-full\" title=\"RHEED diagram: SiC surface structure evolution with Si dose or annealing temperature.\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy1.jpg\" alt=\"RHEED diagram: SiC surface structure evolution with Si dose or annealing temperature.\" width=\"380\" height=\"540\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy1.jpg 380w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy1-211x300.jpg 211w\" sizes=\"auto, (max-width: 380px) 100vw, 380px\" \/><\/a><p id=\"caption-attachment-24913\" class=\"wp-caption-text\">RHEED diagram: SiC surface structure evolution with Si dose or annealing temperature.<\/p><\/div>\n<p>The growth of graphene layers on SiC substrates have opened the way to graphene nano-electronics. Graphene (an hexagonal plane of carbon atoms) may be described either as a metal with a vanishing density of states at the Dirac point or as a semiconductor with a zero band gap. Nevertheless, it behaves as a semiconductor for nanometric dimensions. Its planar structure (opposite to the carbon nanotube case) makes it compatible with usual microelectronics technologies.<\/p>\n<p>Two elaboration processes of graphene thin layers under ultra high vaccuum conditions are studied at IEMN. The first one involves optimisation of the 'standard' graphitization process of SiC substrates by high temperature annealing. RHEED is the preferred in-situ tool for characterization. Other techniques are almost systematically used, either in situ (Low Energy Electron Diffraction, Auger spectroscopy) or ex-situ (photoemission and Raman spectroscopies, atomic force and scanning tunneling microsocopies).<\/p>\n<p>The second approach involves direct growth of graphene by molecular beam epitaxy, with a solid carbon source fitted into the epitaxial set-up. In principle, such techniques should be usable for various substrates able to sustain the required high growth temperature. For example, growth on sapphire results in a polycrystalline structure with nanometric domain size. The most striking results were obtained on SiC substrates, and more particularly on the SiC C face, within the european GRADE project (\"Graphene-based Devices and Circuits for RF Applications\", coordinated by M. Lemme, University of Siegen, Germany). In this case, the standard graphitization process is hardly controllable for mono to few layer thick graphene. On the C face, stacked graphene layers are twisted, as illustrated in the following figure.<\/p>\n<div id=\"attachment_24915\" style=\"width: 1210px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24915\" class=\"wp-image-24915 size-full\" title=\"Stacking of bilayer graphene on the SiC C face: Moire pattern for a 17.9\u00b0 twist angle as imaged by scanning tunneling microscopy (left), corresponding scheme (center) and energy dispersion curve (the Dirac cone) for a ~2\u00b0 twist angle (right), from Razado-Colambo et al., Sci. Reports 6, 27261 (2016).\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy.jpg\" alt=\"Stacking of bilayer graphene on the SiC C face: Moire pattern for a 17.9\u00b0 twist angle as imaged by scanning tunneling microscopy (left), corresponding scheme (center) and energy dispersion curve (the Dirac cone) for a ~2\u00b0 twist angle (right), from Razado-Colambo et al., Sci. Reports 6, 27261 (2016).\" width=\"1200\" height=\"360\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy.jpg 1200w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy-300x90.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy-768x230.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy-1030x309.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/graphene_epitaxy-705x212.jpg 705w\" sizes=\"auto, (max-width: 1200px) 100vw, 1200px\" \/><\/a><p id=\"caption-attachment-24915\" class=\"wp-caption-text\">Stacking of bilayer graphene on the SiC C face: Moire pattern for a 17.9\u00b0 twist angle as imaged by scanning tunneling microscopy (left), corresponding scheme (center) and energy dispersion curve (the Dirac cone) for a ~2\u00b0 twist angle (right), from Razado-Colambo et al., Sci. Reports 6, 27261 (2016).<\/p><\/div>\n<\/div><\/div><\/div><\/section>\n<section class='av_toggle_section av-u4o12j-b701f80a4c03cc05037c2926096f9c8c'  itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\" ><div role=\"tablist\" class=\"single_toggle\" data-tags=\"{All} \"  ><p id='toggle-toggle-id-4' data-fake-id='#toggle-id-4' class='toggler  av-title-above'  itemprop=\"headline\"  role='tab' tabindex='0' aria-controls='toggle-id-4' data-slide-speed=\"200\" data-title=\"Hexagonal boron nitride (hBN) and hBN\/graphene heterostructure studies\" data-title-open=\"\" data-aria_collapsed=\"Click to expand: Hexagonal boron nitride (hBN) and hBN\/graphene heterostructure studies\" data-aria_expanded=\"Click to collapse: Hexagonal boron nitride (hBN) and hBN\/graphene heterostructure studies\">Hexagonal boron nitride (hBN) and hBN\/graphene heterostructure studies<span class=\"toggle_icon\"><span class=\"vert_icon\"><\/span><span class=\"hor_icon\"><\/span><\/span><\/p><div id='toggle-id-4' aria-labelledby='toggle-toggle-id-4' role='region' class='toggle_wrap  av-title-above'  ><div class='toggle_content invers-color'  itemprop=\"text\" ><p>Amongst its many exceptional properties, the two-dimensional (2D) material graphene is famous for its unusually high electronic mobility exceeding 10<sup>5<\/sup> cm\u00b2\/V.s. But, whatever the way of producing the graphene, e.g. mechanical exfoliation or SiC high temperature graphitisation, very specific conditions are required to reach such high quality. In short, the graphene needs to be insulated from any external perturbation, whatever its origin (substrate, adsorbate...). This was achieved for example with suspended nanoribbons, or in rotationally decoupled thick stack of graphene. These solutions are not compatible with realistic devices, among many reasons because it is hardly possible to incorporate efficient gates in such geometry. Indeed, the electronic mobility of graphene in state of the art nanodevices is in the range of 10<sup>3<\/sup> cm\u00b2\/V.s, which is far from these record values.<\/p>\n<p>One solution to this problem has recently emerged, and involves another 2D material, hexagonal boron nitride (hBN). Because of its 2D structure, its roughness remains low, its surface is virtually free of dangling bonds and the charges trapped at the graphene\/hBN interface only come in practice from foreign molecules. These latter tend to form clusters, which reduces the average scattering and results in high mobility graphene material (up to 14.10<sup>4<\/sup> cm\u00b2\/V.s measured at room temperature) while retaining a quite high carrier density (~4.10<sup>12<\/sup> \/cm\u00b2) in hBN\/graphene\/hBN double heterostructures, the main scattering mechanism being phonon related. Hexagonal BN is a large band gap material (indirect band gap of ~6 eV), so that it can be used both as an insulator between the graphene layer and the substrate, as a dielectric layer between the graphene and the gate, and as a tunnel barrier in vertical transport devices. So, hBN is clearly an appealing solution to the problem of making devices exploiting the exceptional transport properties of graphene. Still, there remains a serious roadblock which is the need to make such graphene\/hBN heterostructures by a scalable technique, a mandatory requirement when device applications are eventually targeted.<\/p>\n<p>The graphene MBE chamber has benn equipped with a high-temperature effusion cell for boron, a RF plasma cell for nitrogen and a high temperature gas injector for borazine (B<sub>3<\/sub>N<sub>3<\/sub>H<sub>6<\/sub>. The final goal is to grow graphene\/hBN heterostructures. The figures below illustrate the hBN heteroeitaxy on nickel.<\/p>\n<div id=\"attachment_24919\" style=\"width: 628px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/hbn_hexagonal_boron_nitride.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-24919\" class=\"wp-image-24919 size-full\" title=\"XPS survey (left) and Raman (right) spectra, for hBN grown on Ni from separate B and N cells.\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/hbn_hexagonal_boron_nitride.png\" alt=\"XPS survey (left) and Raman (right) spectra, for hBN grown on Ni from separate B and N cells.\" width=\"618\" height=\"222\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/hbn_hexagonal_boron_nitride.png 618w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2018\/09\/hbn_hexagonal_boron_nitride-300x108.png 300w\" sizes=\"auto, (max-width: 618px) 100vw, 618px\" \/><\/a><p id=\"caption-attachment-24919\" class=\"wp-caption-text\">XPS survey (left) and Raman (right) spectra, for hBN grown on Ni from separate B and N cells.<\/p><\/div>\n<\/div><\/div><\/div><\/section>\n<section class='av_toggle_section av-vzgv57-3cf75b8a05043427546f7136b3ff74ea'  itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\" ><div role=\"tablist\" class=\"single_toggle\" data-tags=\"{All} \"  ><p id='toggle-toggle-id-5' data-fake-id='#toggle-id-5' class='toggler  av-title-above'  itemprop=\"headline\"  role='tab' tabindex='0' aria-controls='toggle-id-5' data-slide-speed=\"200\" data-title=\"Transition metal dichalcogenide epitaxy\" data-title-open=\"\" data-aria_collapsed=\"Click to expand: Transition metal dichalcogenide epitaxy\" data-aria_expanded=\"Click to collapse: Transition metal dichalcogenide epitaxy\">Transition metal dichalcogenide epitaxy<span class=\"toggle_icon\"><span class=\"vert_icon\"><\/span><span class=\"hor_icon\"><\/span><\/span><\/p><div id='toggle-id-5' aria-labelledby='toggle-toggle-id-5' role='region' class='toggle_wrap  av-title-above'  ><div class='toggle_content invers-color'  itemprop=\"text\" ><p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-67819 alignleft\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2-300x244.jpg\" alt=\"\" width=\"300\" height=\"244\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2-300x244.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2-768x625.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2-15x12.jpg 15w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2-845x684.jpg 845w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2-705x574.jpg 705w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureWSe2.jpg 959w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><span style=\"color: #000000\">In the last decades, the exceptional properties of graphene have stimulated materials research and led to numerous proposals for applications. Nevertheless, the absence of a band gap remains an obstacle to the use of graphene in many micro and optoelectronic devices and thus to the development of 2D electronics. Other 2D materials and among them transition metal dichalcogenides (TMDCs), with a band gap of 1 to 2 eV, can then take over. These materials offer properties that are not found in usual semiconductors: absence of dangling surface bonds, nature of the band gap varying with thickness, strong optical absorption, valleytronics,\u2026 In this perspective, to develop its activity on 2D materials, IEMN has launched a research dedicated to the growth of TMDCs by molecular beam epitaxy (MBE) thanks to a Vinci Technologies system connected under ultra-high vacuum to a surface analysis chamber and a III-V semiconductor MBE reactor. The studies are focused on Se-based TMDCs and are concerned with both hybrid III-V\/2Ds heterostructures and TMDC heterostructures.<\/span><\/a><\/p>\n<p><a href=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-67818\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2-300x244.jpg\" alt=\"\" width=\"300\" height=\"244\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2-300x244.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2-768x624.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2-15x12.jpg 15w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2-845x684.jpg 845w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2-705x573.jpg 705w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2024\/07\/figureTaSe2.jpg 961w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<\/div><\/div><\/div><\/section>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"","protected":false},"author":2,"featured_media":0,"parent":16179,"menu_order":25,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-24875","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/pages\/24875","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/page"}],"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=24875"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/pages\/24875\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/pages\/16179"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=24875"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}