Improved Crystallinity of Graphene Grown on Cu/Ni (111) through Sequential Mobile Hot-Wire Heat Treatment

Over the past few years, many efforts have been devoted to growing single-crystal graphene due to its great potential in future applications. However, a number of issues remain for single-crystal graphene growth, such as control of nanoscale defects and the substrate-dependent nonuniformity of graphene quality. In this work, we demonstrate a possible route toward single-crystal graphene by combining aligned nucleation of graphene nanograins on Cu/Ni (111) and sequential heat treatment over pregrown graphene grains. By use of a mobile hot-wire CVD system, prealigned grains were stitched into one continuous film with up to similar to 97% single-crystal domains, compared to graphene grown on polycrystalline Cu, which was predominantly high-angle tilt boundary (HATB) domains. The single-crystallike graphene showed remarkably high thermal conductivity and carrier mobility of similar to 1349 W/mK at 350 K and similar to 33 600 (38 400) cm(2) V-1 s(-1) for electrons (holes), respectively, which indicates that the crystallinity is high due to suppression of HATB domains.

Automated summary

Efforts have been made to grow single-crystal graphene in recent years, but issues such as nanoscale defects control and substrate-dependent nonuniformity remain unresolved. This study demonstrates a possible route to grow single-crystal graphene by combining aligned nucleation and sequential heat treatment. The resulting single-crystallike graphene exhibits high thermal conductivity and carrier mobility.