High-Mobility Epitaxial Graphene on Ge/Si(100) Substrates

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene exhibits unique electronic properties but lacks microelectronic integration.
• Epitaxial graphene on germanium-on-silicon offers a pathway for CMOS-compatible applications.

Purpose of the Study:

• To comprehensively study epitaxial graphene grown on Ge(100) on Si(100) substrates.
• To evaluate its potential for microelectronic applications.

Main Methods:

• Chemical Vapor Deposition (CVD) for graphene growth.
• Angle-resolved photoemission spectroscopy (ARPES) for electronic structure analysis.
• In situ surface transport measurements for carrier mobility assessment.

Main Results:

• Achieved crystalline graphene monolayers with metallic character.
• Obtained room-temperature charge carrier mobilities of 1 × 10^4 cm²/Vs, attributed to quasi-charge neutrality.
• Demonstrated a 30% mobility increase after in situ annealing up to 850 °C.
• Observed weak graphene-Ge interaction and effective delamination.

Conclusions:

• Epitaxial graphene on Ge/Si(100) is a promising material for microelectronics.
• CVD growth and annealing are effective for enhancing graphene quality and performance.
• The Ge(100)-(2 × 1) surface structure indicates weak van der Waals interaction, facilitating integration.