Single-Step Direct Growth of Graphene on Cu Ink toward 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 product development. In this work, we demonstrate the 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 H/CH ratio at higher total gas pressure during the growth. The morphology of Cu ink after the PECVD process and the dependence of the graphene quality on the H/CH ratio may be attributed to the difference in the corresponding electron temperature. Therefore, this study paves a new pathway toward efficient growth of high-quality graphene on Cu ink for applications in flexible electronics and Internet of Things (IoT).