Electrostatic deposition of graphene.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Graphene sheets, particularly monolayer graphene, are frequently found on freshly cleaved Highly Oriented Pyrolytic Graphite (HOPG) surfaces.
• Understanding the properties and transfer of these naturally occurring graphene sheets is crucial for their application.

Purpose of the Study:

• To demonstrate a straightforward electrostatic attraction technique for transferring loose graphene sheets from HOPG to a desired substrate.
• To characterize the transferred graphene sheets, including their thickness and structural integrity, using atomic force microscopy and Raman spectroscopy.

Main Methods:

• Utilizing electrostatic attraction for the transfer of graphene sheets.
• Employing atomic force microscopy (AFM) to measure the thickness of transferred graphene sheets over time.
• Conducting Raman spectroscopy to analyze the structural properties and defect levels of graphene sheets with varying layer numbers.

Main Results:

• Successfully transferred graphene sheets ranging from one to 22 layers thick.
• Observed an increase in the height of a monolayer graphene sheet from ~0.35 nm to ~0.8 nm over several weeks.
• Raman spectroscopy revealed an intense D band in monolayer graphene, attributed to substrate conformity and potential C-C bond disruption, which decreased with increasing layer number.

Conclusions:

• Electrostatic attraction is an effective method for transferring graphene sheets.
• Monolayer graphene exhibits unique structural characteristics and potential instability when transferred, as indicated by the intense D band in Raman spectra.
• The findings provide valuable information for the controlled manipulation and application of graphene materials.