Rapid CVD growth of millimetre-sized single crystal graphene using a cold-wall reactor

Abstract

In this work we present a simple pathway to obtain large single-crystal graphene on copper (Cu) foils with high growth rates using a commercially available cold-wall chemical vapour deposition (CVD) reactor. We show that graphene nucleation density is drastically reduced and crystal growth is accelerated when: i) using ex-situ oxidised foils; ii) performing annealing in an inert atmosphere prior to growth; iii) enclosing the foils to lower the precursor impingement flux during growth. Growth rates as high as 14.7 and 17.5 µm per minute are obtained on flat and folded foils, respectively. Thus, single-crystal grains with lateral size of about one millimetre can be obtained in just one hour. The samples are characterised by optical microscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy as well as selected area electron diffraction (SAED) and low-energy electron diffraction (LEED), which confirm the high quality and homogeneity of the films. The development of a process for the quick production of large grain graphene in a commonly used commercial CVD reactor is a significant step towards an increased accessibility to millimetre-sized graphene crystals.

Anisotropic straining of graphene using micropatterned SiN membranes

“…Circular holes were also investigated, as reported in the literature. 17,28 Large-scale monocrystalline graphene flakes used in the present work were obtained by CVD growth on Cu 29 and transferred on the Si 3 N 4 /Si chips using a standard "bubbling transfer" technique. 30 As sketched in Fig.…”

Perfecting the Growth and Transfer of Large Single-Crystal CVD Graphene: A Platform Material for Optoelectronic Applications

“…Due to safety concerns of introducing oxygen into a system containing highly combustible gases, as was done in the work cited above, we instead utilised the native oxides present in the low -purity Cu substrates [13]. To prevent the reduction of these oxides, annealing was performed in an inert argon atmosphere instead of hydrogen.…”

“…CVD synthesis of graphene Large-crystal graphene was synthesised on commerciallyavailable copper foil with a thickness of 25 µm (99.8% purity, Alfa-Aesar, 13382), which prior to growth was electropolished as described previously [13] in order to remove the surface contamination and improve the surface flatness. This foil is also referred to later in the text as low purity foil (i.e., with a high oxygen content).…”

Tunnel and electrostatic coupling in graphene-LaAlO3/SrTiO3 hybrid systems

“…Single-crystalline graphene flakes typically measuring 100 µm in diameter were grown by CVD on flat, ex situ passivated Cu foils. 21 Graphene crystals were finally deposited on the clean surfaces of LAO/STO heterostructures using a polymer-based transfer process 22 and localized, thanks to the Cr/Au markers. The device architecture was designed taking particular care to avoid spurious electrical losses across the ≈4 nm-thick LAO barrier.…”