BEGIN:VCALENDAR VERSION:2.0 PRODID:IEEE vTools.Events//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:America/Chicago BEGIN:DAYLIGHT DTSTART:20250309T030000 TZOFFSETFROM:-0600 TZOFFSETTO:-0500 RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3 TZNAME:CDT END:DAYLIGHT BEGIN:STANDARD DTSTART:20251102T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0600 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11 TZNAME:CST END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20250731T153557Z UID:418DCDC4-80A9-4777-8745-18D3EC496F15 DTSTART;TZID=America/Chicago:20250801T110000 DTEND;TZID=America/Chicago:20250801T120000 DESCRIPTION:The assembly of van der Waals heterostructures enables the crea tion of devices comprising materials with vastly different electronic band structures\, overcoming the limitations of matching crystal structures. S andwiching an insulator between two (semi-)metallic electrodes constitutes a blueprint for a rational design of tunnelling devices\, where bidirecti onal injection of electrons and holes onto the radiative states leads to e lectroluminescent processes. The nature of the radiative states may be vas tly different\, including Wannier-Mott-like excitons in semiconductors [1\ ,2]\, Frenkel excitons coupled to magnetization textures in ferromagnets [ 3\,4]\, or intradefect transitions raising single photons [5-9]. The struc ture of the barrier can be complex\, involving multiple materials with ato mically precise thickness. Consequently\, the efficiency of the electrolum inescent processes is tunable across multiple orders of magnitude due to t he competition between the tunnelling dynamics and the radiative lifetimes . Alternative tunnelling pathways are activated by distinct device archite ctures at the material level\, governing their spectroscopic characteristi cs.\n\nReferences\n\n[1] K. Walczyk\, G. Krasucki\, K. Olkowska-Pucko\, Z. Chen\, T. Taniguchi\, K. Watanabe\, A. Babiński\, M. Koperski\, M. R. Mo las\, N. Zawadzka\, Optical response of WSe2-based vertical tunneling junc tion\, Solid State Communications 396\, 115756 (2025).\n\n[2] J. Zultak\, S. J. Magorrian\, M. Koperski\, A. Garner\, M. J. Hamer\, E. Tóvári\, K. S. Novoselov\, A. A. Zhukov\, Y. Zou\, N. R. Wilson\, S. J. Haigh\, A. V. Kretinin\, V. I Fal’ko\, R. Gorbachev\, Ultra-thin van der Waals crysta ls as semiconductor quantum wells\, Nature Communications 11 (1)\, 125 (20 20).\n\n[3] M. Grzeszczyk\, S. Acharya\, D. Pashov\, Z. Chen\, K. Vaklinov a\, M. van Schilfgaarde\, K. Watanabe\, T. Taniguchi\, K. S. Novoselov\, M . I. Katsnelson\, M. Koperski\, Strongly Correlated Exciton‐Magnetizatio n System for Optical Spin Pumping in CrBr3 and CrI3\, Advanced Materials 3 5 (17)\, 2209513 (2023).\n\n[4] S. Grebenchuk\, C. McKeever\, M. Grzeszczy k\, Z. Chen\, M. Šiškins\, A. R. C. McCray\, Y. Li\, A. K. Petford‐Lon g\, C. M. Phatak\, D. Ruihuan\, L. Zheng\, K. S. Novoselov\, E. J. G. Sant os\, M. Koperski\, Topological spin textures in an insulating van der Waal s ferromagnet\, Advanced Materials 36 (24)\, 2311949 (2024).\n\n[5] M. Grz eszczyk\, K. Vaklinova\, K. Watanabe\, T. Taniguchi\, K. S. Novoselov\, M. Koperski\, Electroluminescence from pure resonant states in hBN-based ver tical tunneling junctions\, Light: Science & Applications 13 (1)\, 155 (20 24).\n\n[6] J. Howarth\, K. Vaklinova\, M. Grzeszczyk\, G. Baldi\, L. Hagu e\, M. Potemski\, K. S. Novoselov\, A. Kozikov\, M. Koperski\, PNAS 121 (2 3)\, e2401757121 (2024).\n\n[7] Z. Qiu\, K. Vaklinova\, P. Huang\, M. Grze szczyk\, K. Watanabe\, T. Taniguchi\, K. S. Novoselov\, J. Lu\, M. Kopersk i\, Atomic and Electronic Structure of Defects in hBN: Enhancing Single-De fect Functionalities\, ACS Nano 18 (35)\, 24035–24043 (2024).\n\n[8] L. Loh\, J. Wang\, M. Grzeszczyk\, M. Koperski\, G. Eda\, Towards quantum lig ht-emitting devices based on van der Waals materials\, Nature Reviews Elec trical Engineering 1\, 815–829 (2024).\n\n[9] D. Litvinov\, A. Wu\, M. B arbosa\, K. Vaklinova\, M. Grzeszczyk\, G. Baldi\, M. Zhu\, M. Koperski\, Single photon sources and single electron transistors in two-dimensional m aterials\, Materials Science and Engineering: R: Reports 163\, 100928 (202 5).\n\nSpeaker(s): \, Maciej Koperski\n\nVirtual: https://events.vtools.ie ee.org/m/495090 LOCATION:Virtual: https://events.vtools.ieee.org/m/495090 ORGANIZER:cd@anl.gov SEQUENCE:5 SUMMARY:Electron tunnelling in vertical van der Waals junctions for electro luminescent devices URL;VALUE=URI:https://events.vtools.ieee.org/m/495090 X-ALT-DESC:Description: <br /><p class="MsoNormal">The assembly of van der Waals heterostructures enables the creation of devices comprising material s with vastly different electronic band structures\, overcoming the limita tions of matching crystal structures. Sandwiching an insulator between two (semi-)metallic electrodes constitutes a blueprint for a rational design of tunnelling devices\, where bidirectional injection of electrons and hol es onto the radiative states leads to electroluminescent processes. The na ture of the radiative states may be vastly different\, including Wannier-M ott-like excitons in semiconductors <strong>[1\,2]</strong>\, Frenkel exci tons coupled to magnetization textures in ferromagnets <strong>[3\,4]</str ong>\, or intradefect transitions raising single photons <strong>[5-9]</st rong>. The structure of the barrier can be complex\, involving multiple ma terials with atomically precise thickness. Consequently\, the efficiency o f the electroluminescent processes is tunable across multiple orders of ma gnitude due to the competition between the tunnelling dynamics and the rad iative lifetimes. Alternative tunnelling pathways are activated by distinc t device architectures at the material level\, governing their spectroscop ic characteristics.</p>\n<p class="MsoNormal">&nbsp\;</p>\n<p class="MsoNo rmal"><strong>References</strong></p>\n<p class="MsoNormal">[1] K. Walczyk \, G. Krasucki\, K. Olkowska-Pucko\, Z. Chen\, T. Taniguchi\, K. Watanabe\ , A. Babiński\, M. Koperski\, M. R. Molas\, N. Zawadzka\, <em>Optical res ponse of WSe<sub>2</sub>-based vertical tunneling junction</em>\, Solid St ate Communications <strong>396</strong>\, 115756 (2025).</p>\n<p class="Ms oNormal">[2] J. Zultak\, S. J. Magorrian\, M. Koperski\, A. Garner\, M. J. Hamer\, E. T&oacute\;v&aacute\;ri\, K. S. Novoselov\, A. A. Zhukov\, Y. Z ou\, N. R. Wilson\, S. J. Haigh\, A. V. Kretinin\, V. I Fal&rsquo\;ko\, R. Gorbachev\, <em>Ultra-thin van der Waals crystals as semiconductor quantu m wells</em>\, Nature Communications <strong>11 (1)</strong>\, 125 (2020). </p>\n<p class="MsoNormal">[3] M. Grzeszczyk\, S. Acharya\, D. Pashov\, Z. Chen\, K. Vaklinova\, M. van Schilfgaarde\, K. Watanabe\, T. Taniguchi\, K. S. Novoselov\, M. I. Katsnelson\, M. Koperski\, <em>Strongly Correlated Exciton‐Magnetization System for Optical Spin Pumping in CrBr<sub>3</su b> and CrI<sub>3</sub></em>\, Advanced Materials <strong>35 (17)</strong>\ , 2209513 (2023).</p>\n<p class="MsoNormal">[4] S. Grebenchuk\, C. McKeeve r\, M. Grzeszczyk\, Z. Chen\, M. &Scaron\;i&scaron\;kins\, A. R. C. McCray \, Y. Li\, A.&nbsp\;K.&nbsp\;Petford‐Long\, C. M. Phatak\, D. Ruihuan\, L. Zheng\, K. S. Novoselov\, E. J. G. Santos\, M.&nbsp\;Koperski\, <em>Top ological spin textures in an insulating van der Waals ferromagnet</em>\, A dvanced Materials <strong>36 (24)</strong>\, 2311949 (2024).</p>\n<p class ="MsoNormal">[5] M. Grzeszczyk\, K. Vaklinova\, K. Watanabe\, T. Taniguchi \, K. S. Novoselov\, M. Koperski\, <em>Electroluminescence from pure reson ant states in hBN-based vertical tunneling junctions</em>\, Light: Science &amp\; Applications <strong>13 (1)</strong>\, 155 (2024).</p>\n<p class=" MsoNormal">[6] J. Howarth\, K. Vaklinova\, M. Grzeszczyk\, G. Baldi\, L. H ague\, M. Potemski\, K. S. Novoselov\, A.&nbsp\;Kozikov\, M. Koperski\, PN AS <strong>121 (23)</strong>\, e2401757121 (2024).</p>\n<p class="MsoNorma l">[7] Z. Qiu\, K. Vaklinova\, P. Huang\, M. Grzeszczyk\, K. Watanabe\, T. Taniguchi\, K. S. Novoselov\, J. Lu\, M. Koperski\, <em>Atomic and Electr onic Structure of Defects in hBN: Enhancing Single-Defect Functionalities< /em>\, ACS Nano <strong>18 (35)</strong>\, 24035&ndash\;24043 (2024).</p>\ n<p class="MsoNormal">[8] L. Loh\, J. Wang\, M. Grzeszczyk\, M. Koperski\, G. Eda\, <em>Towards quantum light-emitting devices based on van der Waal s materials</em>\, Nature Reviews Electrical Engineering <strong>1</strong >\, 815&ndash\;829 (2024).</p>\n<p class="MsoNormal">[9] D. Litvinov\, A. Wu\, M. Barbosa\, K. Vaklinova\, M. Grzeszczyk\, G. Baldi\, M. Zhu\, M. Ko perski\, <em>Single photon sources and single electron transistors in two- dimensional materials</em>\, Materials Science and Engineering: R: Reports <strong>163</strong>\, 100928 (2025).</p> END:VEVENT END:VCALENDAR