Abstract
The chemical vapor deposition (CVD) of graphene on liquid substrates produces high quality graphene films due to the defect-free and atomically flat surfaces of the liquids. Through the detailed study of graphene growth on liquid Sn using atmospheric pressure CVD (APCVD), the quality of graphene has been found to have a close relationship with hydrogen flow rate that reflects on hydrogen partial pressure inside the reactor (PH2) and hydrogen solubility of the growth substrates. The role of PH2 was found to be crucial, with a low defect density monolayer graphene being obtained in low PH2 (90.4 mbar), while partial graphene coverage occurred at high PH2 (137.3 mbar). To further understand the role of substrate’s composition, binary alloy with compositions of 20, 30, 50, 60 and 80 wt.% tin in copper were made by arc-melting. Graphene quality was found to decrease with increasing the content of copper in the Cu–Sn alloys when grown using the conditions optimised for Sn substrates and this was related to the change in hydrogen solubility and the high catalytic activity of Cu compared to Sn. This shall provide a tool to help optimising CVD conditions for graphene growth based on the properties of the used catalytic substrate.
Highlights
Graphene can be synthesised by a variety of methods including mechanical exfoliation [1], liquid phase exfoliation [2,3,4] and chemical vapor deposition (CVD) [5,6,7,8]
We studied the effect of various process conditions on the growth of CVD graphene on liquid Sn, highlighting the role of hydrogen
The CVD process requires careful tuning of the growth conditions based on the properties of the substrate used as in the case of graphene deposition
Summary
Graphene can be synthesised by a variety of methods including mechanical exfoliation [1], liquid phase exfoliation [2,3,4] and chemical vapor deposition (CVD) [5,6,7,8]. A key parameter in the choice of substrate, and its corresponding growth conditions, is the carbon solubility in the substrate, which is metal dependent and defines the graphene deposition mechanism [15,21]. Carbon atoms prefer to precipitate on regions of the substrate with higher energy such as impurities and grain boundaries [24] Such substrate defects mean that the resulting graphene film is not uniform in thickness, with multi-layer graphene found around the grain boundaries and other surface defects, while randomly orientated thin sheets are found in the other regions. More liquid metals were used to grow graphene via CVD method such as gallium (Ga), indium (In) and tin (Sn) [30,31]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
