Batch synthesis of transfer-free graphene with wafer-scale uniformity

Scalable synthesis of transfer-free graphene over insulators offers exciting opportunity for next-generation electronics and optoelectronics.However,rational design of synthetic protocols to harvest wafer-scale production of directly grown graphene still remains a daunting challenge.Herein we explore a batch synthesis of large-area graphene with wafer-scale uniformity by virtue of direct chemical vapor deposition(CVD)on quartz.Such a controllable CVD approach allows to synthesize 30 pieces of 4-inch graphene wafers in one batch,affording a low fluctuation of optical and electrical properties.Computational fluid dynamics simulations reveal the mechanism of uniform growth,indicating thermal field and confined flow field play leading roles in attaining the batch uniformity.The resulting wafer-scale graphene enables the direct utilization as key components in optical elements.Our method is applicable to other types of insulating substrates(e.g.,sapphire,SiO2/Si,Si3N4),which may open a new avenue for direct manufacture of graphene wafers in an economic fashion.