Patterned growth of graphene over epitaxial catalyst

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Graphene synthesis is crucial for advanced electronic applications.
• Controlling graphene shape and orientation remains a challenge.
• Epitaxial growth offers a route to ordered material structures.

Purpose of the Study:

• To investigate the formation of shaped graphene films.
• To explore the influence of substrate crystallography on graphene morphology.
• To demonstrate the fabrication of graphene-based field-effect transistors.

Main Methods:

• Epitaxial deposition of Cobalt (Co) or Nickel (Ni) films on single-crystal Magnesium Oxide (MgO) substrates.
• Thermal decomposition of polystyrene on epitaxial metal films in vacuum to create pit structures.
• Raman mapping to analyze few-layer graphene formation within pits.
• Transfer of graphene films onto Silicon Dioxide/Silicon (SiO2/Si) substrates for device fabrication.

Main Results:

• Rectangular and triangular pit structures formed, dependent on MgO substrate crystallographic orientation ((001) and (111) planes).
• Few-layer graphene films preferentially formed within these pits.
• Rectangular graphene films were successfully transferred and used to fabricate field-effect transistors.

Conclusions:

• Substrate crystallographic orientation dictates the shape and orientation of graphene.
• This method provides insights into controlled graphene formation mechanisms.
• Potential applications in advanced, tailored graphene growth and device fabrication.