Researchers create one-step graphene patterning method

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Researchers from the University of Illinois at Urbana-Champaign have developed a one-step, facile method to pattern graphene by using stencil mask and oxygen plasma reactive-ion etching, and subsequent polymer-free direct transfer to flexible substrates.

"Significant progress has been made in the direct synthesis of large-area, uniform, high quality graphene films using chemical vapour deposition (CVD) with various precursors and catalyst substrates," explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. "However, to date, the infrastructure requirements on post-synthesis processing for creating interconnects, transistor channels, or device terminals have slowed the implementation of graphene in a wider range of applications."

The researchers’ approach to patterning graphene is based on a shadow mask technique that has been employed for contact metal deposition. According to the researchers, these stencil masks can be easily and rapidly manufactured and are also reusable, enabling cost-effective pattern replication. Since the approach involves neither a polymeric transfer layer nor organic solvents, the team have been able to obtain contamination-free graphene patterns directly on various flexible substrates.

Prof Nam stated that this approach demonstrates a new possibility to overcome limitations imposed by existing post-synthesis processes to achieve graphene micro-patterning.

"This method allows rapid design iterations and pattern replications, and the polymer-free patterning technique promotes graphene of cleaner quality than other fabrication techniques," Prof Nam said. "We have shown that graphene can be patterned into varying geometrical shapes and sizes, and we have explored various substrates for the direct transfer of the patterned graphene."

He envisions this facile approach to graphene patterning will instigate transformative changes in graphene-based device development for applications including flexible circuits/devices and wearable electronics.