Regensburg 2025 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 53: 2D Semiconductors and van der Waals Heterostructures V
HL 53.5: Vortrag
Donnerstag, 20. März 2025, 16:15–16:30, H15
Spatial mapping of the tunable band gaps of bilayer graphene using a WSe2 sensor layer — David Tebbe1, •Alexander Polkowski1, Sophia Lackhoff1, Jonas Blum1, Takashi Taniguchi2, Kenji Watanabe2, Bernd Beschoten1,3, Lutz Waldecker1, and Christoph Stampfer1,4 — 12nd Institute of Physics A, RWTH Aachen University, Aachen — 2National Institute for Materials Science, Namiki, Tsukuba, Japan — 3JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany — 4Peter Grünberg Institute (PGI-9) Forschungszentrum Jülich, Jülich, Germany
Bernal bilayer graphene (BLG) is a 2D material with promising properties for future quantum technologies, due to its tunable band gap and rich correlated phases, which have been detected by electrical transport measurements. However, due to their nature, these measurements have not been able to spatially resolve the bandgap and other electronic properties of BLG. Here, we show optical sensing can overcome this limitation. To achieve this we place a sensing monolayer of WSe2 in direct contact to BLG in a double-gated device structure. The sensor layer hosts excitons, with the ability to sense changes in the electronic configuration of the BLG. The WSe2 hosts Rydberg excitons, which are sensitive to the surrounding dielectric environment and thus sense small changes in carrier density within the BLG, allowing to observe the band gap opening. These excitonic states can be resolved using white light reflection spectroscopy, which allowed us to spatially map the potential landscape in the BLG.
Keywords: Bernal bilayer graphene; WSe2 sensor layer; Optics; Dielectric Screening; Excitonic States