Direct growth of multilayer graphene by precipitation using W capping layer

Abstract

In this study, the direct growth of multilayer graphene from amorphous carbon on a sapphire (0001) substrate by precipitation using a nickel catalyst layer and a tungsten capping layer was examined. The findings revealed that a tungsten carbide layer was formed on top of the catalyst, and this suppressed the diffusion of carbon atoms upwards towards the surface. This caused the graphene layer to precipitate below the catalyst layer rather than above it. Under optimized growth conditions, Raman spectroscopy indicated that a high-quality graphene layer was formed with a low D/G peak intensity ratio of 0.10.

High-Electrical-Conductivity Multilayer Graphene Formed by Layer Exchange with Controlled Thickness and Interlayer

“…Some of these techniques can precisely control the numbers of graphene layers; however, there is difficulty forming thick MLG in the tens of nanometers. Against this backdrop, metal-induced solid-phase crystallization of amorphous carbon (a-C) or polymers has attracted increased attention owing to the direct synthesis of MLG on insulators 12 – 26 . Some of these techniques have allowed synthesis of thick (>5 nm) MLG by controlling the initial thickness of a-C 17 – 26 .…”

“…Against this backdrop, metal-induced solid-phase crystallization of amorphous carbon (a-C) or polymers has attracted increased attention owing to the direct synthesis of MLG on insulators 12 – 26 . Some of these techniques have allowed synthesis of thick (>5 nm) MLG by controlling the initial thickness of a-C 17 – 26 . However, a problem has existed with the uniformity of the MLG layer, which makes it difficult to systematically evaluate the electrical properties of such layers.…”

A light emitter based on practicable and mass-producible polycrystalline graphene patterned directly on silicon substrates from a solid-state carbon source

“…Since both methods require a transferring process, graphene growth methods that allow for direct formation on silicon substrates have been sought aer and several attempts have been reported. [27][28][29][30][31][32][33][34][35][36][37][38][39][40] In this study, we developed a procedure to grow graphene from a solid-state carbon source directly on silicon substrates. To reduce the complexity of the process, the number of steps, and the cost, we have also developed a direct patterning procedure that allows to produce graphene samples with arbitrary position, size, and shape: notably this procedure does not require any dry etching process.…”

Impact of Amorphous-C/Ni Multilayers on Ni-Induced Layer Exchange for Multilayer Graphene on Insulators

“…However, forming thick, uniform MLG is difficult. Conversely, metal-induced solid-phase crystallization of amorphous carbon (a-C) or polymers has been actively studied for the direct synthesis of MLG on insulators. − Some of these techniques have enabled the synthesis of thick (>5 nm) MLG by controlling the initial thickness of a-C. − However, further investigations are required to achieve high-quality MLG on insulators.…”