Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 66: 2D Materials IV: Interfacial Interactions (joint session O/CPP/HL)
O 66.9: Talk
Wednesday, March 18, 2020, 12:30–12:45, WIL B321
Curvature-Induced Charge Baskets 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-70569 Stuttgart, Germany — 2Institut de Physique, École Polytechnique Fédérale de Lausanne, 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 and quantum confinement in monolayer MoS2 on a SiO2/Si substrate using a gate-tunable home-built scanning tunneling microscope at ∼4.9K. Monolayer MoS2 follows surface roughness of the substrate, which exhibits a bending strain with band gap reduction. This band gap reduction at a local regime acts like a potential well leading to charge localization. When the bending strain in MoS2 is larger than 2% at a local region of ∼4 nm, quantum-confined energy levels are observed near the conduction or valence band edge due to the significant band gap reduction of ∼1 eV. Moreover, our theoretical results show that spatial flattening of the conduction (valence) band edge occurs by heavy electron- (hole-) doping of over ∼1013 cm−2. The strain-induced quantum confinement in 2D materials can play an important role in the future development of quantum devices.