Probing the edge-related properties of atomically thin MoS₂ at nanoscale.

ABSTRACT: Defects can induce drastic changes of the electronic properties of two-dimensional transition metal dichalcogenides and influence their applications. It is still a great challenge to characterize small defects and correlate their structures with properties. Here, we show that tip-enhanced Raman spectroscopy (TERS) can obtain distinctly different Raman features of edge defects in atomically thin MoS₂, which allows us to probe their unique electronic properties and identify defect types (e.g., armchair and zigzag edges) in ambient. We observed an edge-induced Raman peak (396?cm^-1) activated by the double resonance Raman scattering (DRRS) process and revealed electron-phonon interaction in edges. We further visualize the edge-induced band bending region by using this DRRS peak and electronic transition region using the electron density-sensitive Raman peak at 406?cm^-1. The power of TERS demonstrated in MoS₂ can also be extended to other 2D materials, which may guide the defect engineering for desired properties.

SUBMITTER: Huang TX 

PROVIDER: S-EPMC6895227 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature