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

• Published in: Advanced materials (Weinheim) 2024-11, Vol.36 (44), p.e2404590-n/a
• Main Authors: Gebeyehu, Zewdu M., Mišeikis, Vaidotas, Forti, Stiven, Rossi, Antonio, Mishra, Neeraj, Boschi, Alex, Ivanov, Yurii P., Martini, Leonardo, Ochapski, Michal W., Piccinini, Giulia, Watanabe, Kenji, Taniguchi, Takashi, Divitini, Giorgio, Beltram, Fabio, Pezzini, Sergio, Coletti, Camilla
• Format: Article
• Language: English
• Subjects: Boron nitride; Carrier mobility; Chemical vapor deposition; Copper; copper film; Cu2O; dry pick‐up; Graphene; high‐mobility; Oxidation; Room temperature; Sapphire; Silicon dioxide; Thin films; Two dimensional materials
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202404590

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. The growth via chemical vapor deposition of decoupled graphene on crystalline Cu(111) films deposited on sapphire is introduced. The resulting graphene is lying atop a thin Cu2O layer and is charge neutral, low strained, and easy to transfer. Electrical transport measurements reveal excellent room temperature carrier mobilities, exceeding 105 cm2 V−1 s−1 upon encapsulation in hexagonal boron nitride, thus opening realistic pathways for high‐performance next‐generation applications.