Investigating Local Electron Transport Dynamics in Layer-Dependent MoS₂/RGO Heterostructures Using Conductive Atomic...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Layer-dependent physical properties of 2D materials are vital for science and technology.
• Understanding local electrical conductivity at the atomic scale is currently limited.

Purpose of the Study:

• To investigate the layer-dependent physical properties of large-sized monolayer molybdenum disulfide (MoS₂).
• To analyze the structural, optical, and electrical characteristics of MoS₂/reduced graphene oxide (RGO) heterostructures.

Main Methods:

• Polydimethylsiloxane (PDMS)-assisted mechanical exfoliation and micromanipulation to obtain large monolayer MoS₂.
• Raman spectroscopy, photoluminescence (PL) spectroscopy, atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), and conductive AFM (CAFM) were employed.
• Characterization of MoS₂/RGO heterostructures with varying MoS₂ layer thicknesses.

Main Results:

• Raman and PL spectra confirmed the distinct structure and optical properties of monolayer MoS₂.
• AFM confirmed MoS₂ and RGO thicknesses.
• KPFM and CAFM revealed layer-dependent work function (WF) and Schottky barrier height (Φ_B) in MoS₂/RGO heterostructures.
• Increased MoS₂ layer thickness reduced Φ_B and increased WF, indicating altered interfacial electronic structure.

Conclusions:

• The study provides a deeper understanding of the optical, structural, and electrical properties of MoS₂/RGO heterostructures.
• Layer-dependent behavior of WF and Φ_B highlights the importance of interface engineering in 2D material-based devices.