Synthesis of few-layer graphene via microwave plasma-enhanced chemical vapour deposition

Abstract

If graphene is ever going to live up to the promises of future nanoelectronic devices, an easy and cheap route for mass production is an essential requirement. A way to extend the capabilities of plasma-enhanced chemical vapour deposition to the synthesis of freestanding few-layer graphene is presented. Micrometre-wide flakes consisting of four to six atomic layers of stacked graphene sheets have been synthesized by controlled recombination of carbon radicals in a microwave plasma. A simple and highly reproducible technique is essential, since the resulting flakes can be synthesized without the need for a catalyst on the surface of any substrate that withstands elevated temperatures up to 700• C. A thorough structural analysis of the flakes is performed with electron microscopy, x-ray diffraction, Raman spectroscopy and scanning tunnelling microscopy. The resulting graphene flakes are aligned vertically to the substrate surface and grow according to a three-step process, as revealed by the combined analysis of electron microscopy and x-ray photoelectron spectroscopy.

Plasma-enhanced chemical vapor deposition of graphene on copper substrates

“…There have been some reports of plasma-based methods to decrease the process temperature including the use of microwave plasma CVD to synthesize graphene on nickel foil, 7 surface wave plasma CVD to synthesize graphene at low temperatures in the range of 300 • C to 400 • C on large area conductive electrodes 8,9 and the plasma-assisted deposition of graphene on copper foils at temperatures down to 600 • C. [10][11][12] Although these works show that PECVD is a promising method for the synthesis of graphene, the resulting carbon structures often lack of quality being FLG with considerable amount of defects. 11,12 The high defect density in PECVD graphene is referred to energetic particles from the plasma interacting with the growing surface.…”

“…11,12 The high defect density in PECVD graphene is referred to energetic particles from the plasma interacting with the growing surface. Nevertheless there have been experiments proving that SLG of good quality can be deposited by plasma-assisted methods.…”

The effect of surfactants and their concentration on the liquid exfoliation of graphene

“…12 Chemical vapor deposition (CVD) method of synthesizing few layer graphene (FLG) was first discovered in 2006 13 , and to date, mature millimeter-sized monolayer graphene sheets can be achieved and transferred to many substrates by plasma-enhanced CVD process. 14 But direct growth of large-sized graphene and on different substrates still need to be explored and industrial-scale synthesis is to be solved. Chemical reduction of graphene oxide (rGO) was thought to be a promising approach, as graphene oxide (GO) can be easily exfoliated through sonication in liquid phase, 15,16 and chemical reduction process can decrease the functional defects produced by oxidation.…”

Synthesis &Structural Study on Graphene Nano Particles

“…It is also found that G band is broadened and shifted to 1572 cm -1 [60]. In addition, the D band is observed at 1336 cm -1 becomes prominent, is indicating the reduction in size of the plane sp 2 domains, possibly due to the extensive oxidation [14]. Similarly, we observe the major peaks of G and D bands for the graphene at 1336 cm -1 and 1572 cm -1 indicating the high purity of carbon compound existing in singular layers stacking.…”