ScN/GaN(1-100): a new platform for the epitaxy of twin-free metal-semiconductor heterostructures
| Dates: | 24 January 2024 |
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| Times: | 13:00 - 14:00 |
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| What is it: | Seminar |
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| Organiser: | Photon Science Institute |
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| Who is it for: | University staff, Current University students |
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| Speaker: | Dr. Philipp John |
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Join us for this PSI seminar with guest speaker Dr. Philipp John. Dr. John studies the molecular beam epitaxy of rock-salt ScN on the wurtzite GaN(1-100) surface. To this end, ScN is grown on free-standing GaN(1-100) substrates and self-assembled GaN nanowires that exhibit (1-100) sidewalls. On both substrates, ScN crystallizes twin-free thanks to a specific epitaxial relationship, namely ScN(110)001||GaN(1-100)000-1, providing a congruent, low-symmetry GaN/ScN interface. The 13.1% uniaxial lattice mismatch occurring in this orientation mostly relaxes within the first few monolayers of growth by forming a coincidence site lattice, where 7 GaN planes coincide with 8 ScN planes, leaving the ScN surface nearly free of extended defects. Overgrowth of the ScN with GaN leads to a kinetic stabilization of the zinc blende phase, that rapidly develops wurtzite inclusions nucleating on {111} nanofacets, commonly observed during zinc blende GaN growth. Our ScN/GaN(1-100) platform opens a new route for the epitaxy of twin-free metal-semiconductor heterostructures made of closely lattice-matched GaN, ScN, HfN and ZrN compounds.
Speaker
Dr. Philipp John
Organisation: Paul-Drude-Institute for Solid State Electronics
Biography: Philipp John 2017: M. Sc. in Chemistry at University of Bochum (Germany), containing an exchange semester in Helsinki, Finland 2017-2018: Research assistant at Fraunhofer Institute for Solar Energy Systems, Freiburg (Germany) 2018-2021: PhD in Physics at CNRS-CRHEA (associated to Université Côte d'Azur), Valbonne (France), obtained young researcher award given by the city of Nice 2021-2022: Post-doc at Fraunhofer Institute for Solar Energy Systems, Freiburg (Germany) 2022-2024: Post-doc at Paul-Drude-Institute for Solid State Electronics, Berlin (Germany)
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