Defect engineering as a versatile route to estimate various scattering mechanisms in monolayer graphene on solid...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Carrier mobility in graphene monolayers is highly sensitive to experimental conditions and growth methods.
• Understanding scattering mechanisms is crucial for optimizing graphene-based electronic devices.
• Graphene on solid substrates like silicon dioxide (SiO2) presents unique challenges due to substrate interactions.

Purpose of the Study:

• To systematically investigate scattering mechanisms limiting carrier mobility in graphene monolayers on SiO2.
• To correlate defect engineering in graphene with observed carrier mobility variations.
• To differentiate the roles of various scattering sources at different temperatures.

Main Methods:

• Graphene monolayers were produced via liquid phase exfoliation of graphite in solvents with varying dielectric constants (2.5-64).
• Defect engineering was employed to modify graphene properties.
• Lattice defects were characterized using scanning tunneling microscopy (STM) and Raman spectroscopy.
• Electrical measurements were correlated with spectroscopic data.

Main Results:

• Remote interfacial phonons in SiO2 were identified as the primary limitation for carrier mobility at room temperature.
• Substrate impurities and Raman-active point defects within the graphene lattice were found to be dominant scatterers at low temperatures.
• A clear correlation was established between Raman spectral features and electrical transport properties.

Conclusions:

• The study elucidates the dominant scattering mechanisms governing carrier mobility in graphene on SiO2 at different temperature regimes.
• Defect engineering and substrate properties significantly influence graphene's electronic performance.
• This work provides insights for designing high-mobility graphene devices by controlling scattering sources.