Amplitude ratio data of hexagonal structures prepared by Chemical Vapor Deposition on copper foil substrates
Ellipsometric parameters data use potential is assessment of graphene layer thickness on different surfaces. Data shows dependence of the amplitude ratio on the surface roughness of copper foil, gas concentrations and reaction zone conditions. Multiple amplitude ratio data files were collected from V-VASE Ellipsometer for various hexagonal structures on bare and treated copper foil substrates. Kaleidagraph 4.0 software was used to generate Fig. 1 a-d based on foil thickness and gas flow. Fig. 1 shows the amplitude ratio of materials within the graphite box (blue) and outside (green) on acetic-acid, treated copper foil thickness of (a) and (b) 25 µm, (c) and (d) 75 µm, and methane flow rate of (a), (c) 0.3 sccm and (b), (d) 0.2 sccm as well as control samples (yellow). Matched amplitude ratio was obtained only for 75 µm thick acetic acid treated copper foil at a low methane flow rate of 0.2 sccm. Moreover, Fig. 2 a,b show that the amplitude ratio of 75 µm bare copper foil and 75 µm electro-polished copper foil substrates at methane flow rates of 0.3 sccm were unmatched. This data is useful because it enables a non-destructive analysis of materials to probe materials class and uniformity.
Steps to reproduce
Synthesis of materials on copper foil substrates was carried out in a FirstNano EasyTube 2000 Chemical Vapor Deposition system at varying conditions. For each experiment, two sets of copper foil substrates were placed within and outside of the graphite box. Each set was composed of 25 µm and 75 µm acetic acid treated copper foil, 75 µm bare copper foil, and 75 µm electro-polished copper foil substrates. The chamber was heated to 1075 ºC under flow of 4900 sccm of Argon for 60 minutes at atmospheric conditions. The samples were kept at 1075 ºC under flow of 150 sccm H2 for 5 minutes to deoxidize the catalysts. Then, 0.2-0.3 sccm of CH4 and 35 sccm of ethylene were added for 60 min. Then, the furnace was cooled to room temperature in Ar gas to prevent oxidation of materials. Ellipsometric parameters of materials on copper foil substrates were obtained using V-VASE Ellipsometer from JA Woollam Co. at incidence angle of 70 degrees. Data of the amplitude ratio of materials on copper foil substrates was collected based on copper foil substrate thickness and methane flow rate.