Single-Step Direct Growth of Graphene on Cu Ink towards Flexible Hybrid Electronic Applications by Plasma-Enhanced Chemical Vapor Deposition

Highly customized and free-formed products in flexible hybrid electronics (FHE) require direct
pattern creation such as inkjet printing (IJP) to accelerate the product development. In this work,
we demonstrate direct growth of graphene on Cu ink deposited on polyimide (PI) by means of
plasma enhanced chemical vapor deposition (PECVD), which provides simultaneous reduction,
sintering and passivation of the Cu ink and further reduces its resistivity. We investigate the
PECVD growth conditions for optimizing the graphene quality on Cu ink, and find that the defect
characteristics of graphene are sensitive to the H2/CH4 ratio at higher total gas pressure during the
growth. The morphology of Cu ink after the PECVD process and the dependence of graphene
quality on the H2/CH4 ratio may be attributed to the difference in the corresponding electron
temperature. This study therefore paves a new pathway towards efficient growth of high-quality
graphene on Cu ink for applications to flexible electronics and Internet of Things (IoT).