Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 48: Poster: 2D Materials beyond Graphene: TMDCs, Silicene and Relatives
O 48.20: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster A
Tuning optoelectronic properties on 2D material devices — •Nieves Morquillas1, Saül Veléz1,3, Felix Casanova1,2, Luis Hueso1,2, Reyes Calvo1,2, and Jose Ignacio Pascual1,2 — 1CIC nanoGUNE, 20018 San Sebastian (Spain) — 2Ikerbasque, 48011 Bilbao (Spain) — 3Department of Materials, ETH Zürich, 8093 Zürich (Switzerland)
Transition metal dichalcogenides are promising materials for optoelectronis due to their tunability. We characterize the optoelectronic properties of semiconducting 2D devices by combined photoluminescence and electric transport measurements in a scanning photocurrent microscope (SPCM). We study the photocurrent created at Schottky barriers of MoS2 devices, including systems with an interface between 1L and 2L showing a potential barrier at the boundary. We also investigated a heterostructure of MoS2 on top of NbSe2, a strong electron acceptor, where we find areas at the heterostructure with a high on/off current ratio.
Another tunable property is the pseudo-spin. For an odd number of layers, inversion symmetry is broken and thus it is possible to tune a new degree of freedom, the valley. Here we investigate the effect of a ferrimagnetic substrate (Yttrium Iron Garnet, YIG) on the pseudo-spin of a WSe2 single layer by circularly polarized light in a scanning confocal microscope (SCFM). The ferrimagnetic substrate has a characteristic magnetic domain arrangement with an effective out-of-plane magnetic field. Contrary to expected, we observed a stronger effect from the substrate roughness than from the effective magnetic field.