Substrate screening for superclean graphene growth using firstprinciples calculations

Suppressing the formation of amorphous surface carbon and contaminants during the preparation of graphene by chemical vapor deposition remains an ongoing issue.Herein,we analyzed how substrate characteristics affect graphene quality by simulating margin extension,the nucleation process,and defect pegging configurations on mono-crystalline oriented metal substrates with the aim of enhancing graphene cleanliness.Defect formation energy and nucleation potential,which are indirect substrate–graphene interaction features,were found to appropriately evaluate graphene quality.The crystallographic orientation of the metal substrate was discovered to be critical for producing superclean graphene.A low graphene defect density and high nucleation rate on the Cu(100)facet guarantee growth of high-quality graphene,especially in terms of suppressing the formation of amorphous carbon.In addition,rapid kink growth and self-healing on the Cu(100)facet facilitate rapid graphene synthesis,which is also promoted by rapid kink splicing and margin self-repair on this facet.This study provides theoretical insight useful for the synthesis of superclean graphene.

The role of Cu crystallographic orientations towards growing superclean graphene on meter-sized scale

Chemical vapor deposition(CVD)-grown graphene films on Cu foils,exhibiting fine scalability and high quality,are still suffering from the adverse impact of surface contamination,i.e.,amorphous carbon.Despite the recent successful preparation of superclean graphene through Cu-vapor-assisted reactions,the formation mechanism of amorphous carbon remains unclear,especially with regard to the functions of substrates.Herein,we have found that the crystallographic orientations of underlying metal substrates would determine the cleanness of graphene in such a way that slower diffusion of active carbon species on asformed graphene-Cu(100)surface is the key factor that suppresses the formation of contamination.The facile synthesis of clean graphene is achieved on the meter-sized Cu(100)that is transformed from the polycrystalline Cu foils.Furthermore,a clean surface of graphene on Cu(100)ensures the reduction of transfer-related polymer residues,and enhanced optical and electrical performance,which allows for versatile applications of graphene in biosensors,functioning as flexible transparent electrodes.This work would offer a promising material platform for the fundamental investigation and create new opportunities for the advanced applications of high-quality graphene films.