Regensburg 2022 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 3: 2D Materials 1 (joint session HL/CPP/DS)
DS 3.9: Vortrag
Montag, 5. September 2022, 12:15–12:30, H36
Infrared photocurrent in transition-metal dichalcogenide heterostructures — Jeong Woo Han1, Peize Han2, Yijing Liu2, Paola Barbara2, Thomas E. Murphy3, and •Martin Mittendorff1 — 1Universität Duisburg-Essen, Fakultät für Physik, 47057 Duisburg, Germany — 2Georgetown University, Department of Physics, Washington, 20057 DC, USA — 3University of Maryland, Institute for Research in Electronics and Applied Physics, College Park, 20740 MD, USA
Heterostructures of transition metal dichalcogenites (TMDCs) have characteristic optical properties like the interlayer excitons due to the band offset between two adjacent TMDC layers. Such heterostructures are promising candidates for photodetectors with higher efficiencies compared to a single TMDC layer, furthermore, the interlayer excitation enables photocurrents at photon energies below the direct bandgap of each of the layers. Here we present measurements on a MoS2/WS2 heterostructure at photon energies of around 800 meV, which is significantly below the interlayer exciton. The cross-shaped structure of our samples allows measurements of the heterostructure as well as each individual layer. While at high photon energies photocurrents are observed in each of the layers, the low photon energy only leads to a photocurrent when the heterostructure is illuminated. We interpret this effect to be caused by intraband absorption and subsequent interlayer tunneling.