Reproducible Synthesis of 6-Inch Adlayer-Free Graphene Single Crystals via Interfacial Chemical Potential Engineering

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Chemical vapor deposition (CVD) synthesis of monolayer graphene single crystals on Cu(111) is a key method for scalable production.
• Adlayer formation during CVD graphene growth compromises uniformity and homogeneity, hindering widespread application.
• Existing adlayer elimination methods have limited process windows, affecting scalability and reproducibility.

Purpose of the Study:

• To identify the critical factors influencing adlayer formation during graphene CVD.
• To develop a reproducible strategy for growing adlayer-free monolayer graphene single crystals on a large scale.
• To improve the quality and uniformity of CVD-grown graphene for electronic applications.

Main Methods:

• Identified carbon chemical potential as the key factor for adlayer formation.
• Developed an interfacial chemical potential engineering strategy using symmetric dual-catalytic confinement.
• Regulated the chemical potential of active carbon species to enlarge the process window for adlayer-free growth.

Main Results:

• Successfully produced twenty 6-inch monolayer graphene wafers in a single batch, free of adlayers.
• Achieved a 4-orders-of-magnitude reduction in adlayer density with an expanded reaction window.
• Demonstrated improved transfer intactness and electrical uniformity, with average carrier mobility of ~8461 cm² V⁻¹ s⁻¹ and sheet resistance of 401 ± 12 Ω sq⁻¹.

Conclusions:

• The interfacial chemical potential engineering strategy effectively suppresses adlayers during graphene CVD.
• This approach establishes a reliable and scalable pathway for wafer-scale monolayer graphene single crystal production.
• The improved graphene quality paves the way for advanced electronic device applications.