Silicon oxide particles size evolution during CVD graphene growth on Cu substrates

Chemical vapor deposition (CVD) on metal substrates is presently the remarkably route for the synthesis of high-quality continuous graphene films at a large scale. Whereas, during the thermal processing procedure in the quartz tube, the formation of silicon oxide particles would degrade the performance of graphene. To better understand the origin of these particles , a series of CVD graphene growth experiments with were conducted on the Cu substrates. In this paper, we investigated the main component and morphology of the particles by X-Ray photoelectron spectroscopy (XPS), energy dispersive spectrometry (EDS) measurement in scanning electron microscopy (SEM) and revealed that the silicon oxide particles gradually increased in diameter across the graphene films on the Cu surface, which was found to be correlated with the working time of the quartz products. Raman spectroscopy was also applied to prove the drawback consequence of the contamination on the quality of the CVD graphene film. To mitigate this issue, we further propose a modification of the CVD system that a coaxial alumina or BN tube inside the quartz tube to screen the contaminants bringing about improved graphene growth.