AI Summary & Key Takeaways
AI InsightThe results show that the grain size calculated from XRD data is decreasing as the thickness increases except for 25 μm thick copper.
📌 3 Key Takeaways
Abstract
The quality of the graphene grown on the top and subside of copper substrate with different thicknesses was investigated. Graphenes were grown on the 9, 25, 150 and 250 μm thickness copper substrates with Low-Pressure CVD by using CH4 process gas. Copper substrates were examined through XRD/XRF analysis. Graphenes that are grown on the surface of the copper substrate were characterized by Raman spectrometer. The results show that the grain size calculated from XRD data is decreasing as the thickness increases except for 25 μm thick copper. Besides the micro-strain in the structure is increasing according to the thickness of substrate. Raman spectroscopy results show that the graphene grown on the top surface of the 9 μm thick substrate is purely single-layer. The other samples consist of not only single-layer graphene but also few-layer graphene domains. When we look at I2D/IG ratios for samples on the top surface of coppers, the graphene doping decreases together with increasing thickness of substrate. At the same time, graphenes on the copper subsurface have blueshift and higher FWMH values. It reveals there is a close relation between the graphene and the copper subsurface. The graphene grown on the top side of the 150 μm copper has the typical attribute of suspended single-layer graphene with the redshift of a narrow 2D peak and I2D/IG ≈ 4. In this study, the best sample is obtained on the top surface of the 150 μm thick copper substrate. The large single-layer graphene is depend on microstrain rather than grain orientation