In Situ Growth of CVD Graphene Directly on Dielectric Surface toward Application

Abstract

A technique for the in situ growth of patterned graphene by CVD has been achieved directly on insulating substrates at 800 °C. The graphene growth is catalyzed by a Ni−Cu alloy sacrificial layer, which integrates many advantages such as being lithography-free, and almost wrinkle-free, with a high repeatability and rapid growth. The etching method of the metal sacrificial layer is the core of this technique, and the mechanism is analyzed. Graphene has been found to play an important role in accelerating etching speeds. The Ni−Cu alloy exhibits a high catalytic activity, and thus, high-quality graphene can be obtained at a lower temperature. Moreover, the Ni−Cu layer accommodates a limited amount of carbon atoms, which ensures a high monolayer ratio of the graphene. The carbon solid solubility of the alloy is calculated theoretically and used to explain the experimental findings. The method is compatible with the current semiconductor process and is conducive to the industrialization of graphene devices.

The Growth of Graphene on Ni–Cu Alloy Thin Films at a Low Temperature and Its Carbon Diffusion Mechanism

“…It shows that with the increase of Ni percentage, the graphene grown at 600 °C becomes thicker and appears with uneven layer distribution. Even though such a phenomenon was observed in our previous work [15] on the graphene growth at a higher temperature, i.e., 800 °C, it seemed contrary to our expectations, considering the limited carbon solid solubility at low temperatures. We found that this phenomenon could no longer be explained by the known mechanism of carbon atom segregation.…”

“…Ni is known to be more catalytic than Cu in graphene growth [14]. Previously, we have studied the growth of graphene at 800 °C and found that with the increase of Ni composition in Ni–Cu alloys, the quality of graphene increased gradually [15]. However, the carbon solid solubility of Ni–Cu alloy also increases with the increase of Ni composition [16].…”

“…However, the carbon solid solubility of Ni–Cu alloy also increases with the increase of Ni composition [16]. We found that when the percentage of Ni reached 50%, graphene showed notable multi-layer areas [15]. Therefore, at 800 °C, we controlled the proportion of Ni to Cu to be 1:2.…”

“…One of the applications of low temperature growth is the combination with direct growth technology, which makes it possible to directly grow graphene on a variety of substrates that cannot withstand very high temperatures. We combined this 600 °C graphene growth method with our previously-reported in situ growth technique [15,29] and obtained wafer-scale patterned graphene directly on the SiO 2 /Si substrate.…”

Chemical Vapour Deposition of Graphene—Synthesis, Characterisation, and Applications: A Review

“…A study by Dong et al focuses on the in situ growth of patterned graphene structures via a vertical cold wall CVD reactor using a SiO 2 /Si substrate and Ni-Cu alloy sacrificial layer as a metal catalyst at 800 • C. The Ni-Cu alloy is particularly suitable to be used as a growth substrate for graphene at low temperatures due to its catalytic nature, low carbon solubility (about 4.3 times lower than that of pure Ni), and more uniform grain size compared with Cu and Ni. Due to these advantages of the Ni-Cu alloy, the graphene film obtained by the proposed method exhibited excellent uniformity and a high monolayer ratio [89].…”