Decoupled High-Mobility Graphene on Cu(111)/Sapphire via Chemical Vapor Deposition

Adv Mater. 2024 Nov;36(44):e2404590. doi: 10.1002/adma.202404590. Epub 2024 Sep 9.

Abstract

The growth of high-quality graphene on flat and rigid templates, such as metal thin films on insulating wafers, is regarded as a key enabler for technologies based on 2D materials. In this work, the growth of decoupled graphene is introduced via non-reducing low-pressure chemical vapor deposition (LPCVD) on crystalline Cu(111) films deposited on sapphire. The resulting film is atomically flat, with no detectable cracks or ripples, and lies atop of a thin Cu2O layer, as confirmed by microscopy, diffraction, and spectroscopy analyses. Post-growth treatment of the partially decoupled graphene enables full and uniform oxidation of the interface, greatly simplifying subsequent transfer processes, particularly dry-pick up - a task that proves challenging when dealing with graphene directly synthesized on metallic Cu(111). Electrical transport measurements reveal high carrier mobility at room temperature, exceeding 104 cm2 V-1 s-1 on SiO2/Si and 105 cm2 V-1 s-1 upon encapsulation in hexagonal boron nitride (hBN). The demonstrated growth approach yields exceptional material quality, in line with micro-mechanically exfoliated graphene flakes, and thus paves the way toward large-scale production of pristine graphene suitable for high-performance next-generation applications.

Keywords: Cu2O; chemical vapor deposition; copper film; dry pick‐up; graphene; high‐mobility.