Metal-dielectric transition in Sn-intercalated graphene on SiC(0001)

Area of Science:

• Materials Science
• Surface Science
• Condensed Matter Physics

Background:

• Graphene grown on silicon carbide (SiC) substrates often requires a buffer layer for high quality.
• Understanding interfacial reactions is crucial for utilizing graphene in electronic devices.

Purpose of the Study:

• To investigate the intercalation of tin (Sn) into a graphene buffer layer on a 4H-SiC(0001) substrate.
• To characterize the resulting interfacial layers and their impact on graphene structure.
• To explore the thermal stability and potential applications of these interfacial layers.

Main Methods:

• Spectroscopic photoemission
• Low-energy electron microscopy (LEEM) in various operational modes

Main Results:

• Formation of both tin silicide (SnSiₓ) and tin oxide (SnOₓ) interfacial layers beneath the graphene buffer.
• Conversion of the buffer layer into quasi-free-standing monolayer graphene.
• Observation of a reversible transition between silicide and oxide phases upon exposure to ambient conditions and subsequent annealing.
• Detailed insights into the formation processes and thermal stability of the interlayers.

Conclusions:

• Tin intercalation effectively transforms the buffer layer graphene into a quasi-free-standing monolayer.
• The reversible metal-dielectric transition at the interface presents opportunities for interface engineering in graphene-based electronics.