Quantum Transport and Molecular Sensing in Reduced Graphene Oxide Measured with Scanning Probe Microscopy

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Reduced graphene oxide (rGO) is a promising material for electronic applications.
• Understanding charge transport mechanisms in rGO is crucial for device optimization.

Purpose of the Study:

• To investigate local electronic transport in rGO devices using scanning probe microscopy.
• To demonstrate the tunability of quantum transport via electrostatic gating.
• To explore the chemical sensing capabilities of rGO.

Main Methods:

• Combined scanning probe microscopy (SPM) and electrical measurements.
• Scanning gate microscopy (SGM) for local electrostatic control.
• Scanning impedance microscopy (SIM) for Fermi level analysis.
• Exposure to electron-withdrawing molecules (acetone) for sensing evaluation.

Main Results:

• Local electrostatic gating with an atomic force microscope (AFM) tip significantly tunes source-drain current in rGO.
• SGM confirmed a p-type response, while SIM showed Fermi level shifts under gating.
• Defect-mediated scattering and AFM tip-induced Fermi-level shifts influence transport.
• rGO devices demonstrated reversible chemical sensing of acetone, with increased carrier density.

Conclusions:

• Nanoscale electrostatic control strongly influences charge transport in rGO.
• The findings link local gating effects to macroscopic sensing performance.
• rGO shows significant potential for nanoscale electronics and chemical sensors.