Controlled Doping in Graphene Monolayers by Trapping Organic Molecules at the Graphene-Substrate Interface

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene monolayers exhibit unique electronic properties.
• Controlling charge carrier concentration in graphene is crucial for device applications.
• Organic molecules offer potential for modifying graphene's electronic behavior.

Purpose of the Study:

• To demonstrate controlled doping of graphene monolayers using organic molecules.
• To investigate the charge-transfer mechanism between organic molecules and graphene.
• To correlate experimental observations with theoretical calculations.

Main Methods:

• Fabrication of graphene field-effect transistors.
• Trapping organic molecules between graphene and substrates.
• Characterization using Raman spectroscopy, infrared spectroscopy, and electrical measurements.
• Theoretical validation using density functional theory (DFT) calculations.

Main Results:

• Demonstrated controllable n-type and p-type doping in graphene via organic molecule trapping.
• Observed shifts in Raman peaks and Dirac points indicating doping.
• Confirmed charge-transfer interaction through experimental and DFT analyses.
• Identified donor and acceptor characteristics of organic molecules.

Conclusions:

• Organic molecule trapping provides a viable method for controlled graphene doping.
• Charge-transfer interaction is the key mechanism for doping graphene with organic molecules.
• This approach enables tunable electronic properties of graphene for advanced applications.