Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 78: Poster Session VI: 2D Materials: Electronic structure, excitations, etc. II
O 78.10: Poster
Mittwoch, 3. März 2021, 13:30–15:30, P
Gate-Tunable Curvature-Induced Charge Localization in Two-Dimensional Semiconducting Monolayers — •bong gyu shin1, jz-yuan juo1, soon jung jung1, and klaus kern1,2 — 1Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, DE-70569Stuttgart, Germany — 2Institut de Physique, École Polytechnique Fédérale deLausanne, CH-1015 Lausanne, Switzerland
The localized quantum states in two-dimensional (2D) materials are attractive for valley- and spin- related optoelectronics or other quantum applications. However, achieving these quantum states is still challenging due to technical difficulties. Here, we investigated strain-induced charge localization in monolayer MoS2 on SiO2/Si using a gate-tunable home-built scanning tunneling microscope at ∼4.9K. A MoS2 monolayer follows surface roughness of the substrate, exhibiting random distribution of bending strain with band gap reduction at a local region, acting like a potential well leading to charge localization. At higher electron doping levels, the tunneling-barrier-height over high curvature regions is reduced since localized electron charges lower the local work function. Moreover, we observed the spatial flattening of the conduction (valence) band edge over the band gap fluctuation at electron- (hole-) doping of ∼1013 cm−2. In our theoretical calculations, the trends of local work function and spatial flattening of band edges by doping levels were confirmed in various thin 2D semiconductors, providing the general mechanism of charge localization via curvature effects.