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

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.

How Moorfield products helped:

nanoPVD-T15A

Cu Film Deposition

The Cu film was deposited on single-side-polished single-crystalline 2″ c-plane sapphire (i.e., α- Al2O3(0001)) wafers purchased from Roditi and Silian. The wafers were cleaned by sonication in acetone and isopropanol and then with “piranha” solution (i.e., H2SO4:H2O2 3:1) for 15 min, followed by rinsing with DI water. A Cu film with a nominal thickness of ≈3 µm was deposited using a thermal evaporator (Moorfield Nano PVD-T15A) at a deposition rate ≈0.1 nm s−1 and pressure ≈1.6 × 10−5 mbar.

Open Access publication details: