The new production method was developed by engineers at the University of Exeter. It consists in creating entire device arrays directly on the copper substrates used for the commercial production of graphene, after which complete and fully-functional devices can be transferred to a substrate of choice.
This process has been demonstrated by producing a flexible and completely transparent graphene oxide-based humidity sensor. Not only does this device outperform currently-available commercial sensors, but it’s also cheap and easy to produce using common wafer-scale or roll-to-roll manufacturing techniques.
‘The conventional way of producing devices using graphene can be time-consuming, intricate and expensive and involves many process steps including graphene growth, film transfer, lithographic patterning and metal contact deposition,’ explains Prof David Wright from Exeter’s Engineering department. ‘Our new approach is much simpler and has the very real potential to open up the use of cheap-to-produce graphene devices for a host of important applications from gas and bio-medical sensors to touch-screen displays.’
One of team’s main objectives was to increase the range of surfaces that graphene devices can be put on. Whilst the demonstrated humidity sensor was integrated in a plastic film, other materials such as silicon and textiles can also be considered.
Professor Monica Craciun from Exeter’s engineering department and co-author of the paper published in the journal 2D Materials, is confident that this breakthrough will indeed boost the graphene market: ‘The University of Exeter is one of the world’s leading authorities on graphene, and this new research is just the latest step in our vision to help create a graphene-driven industrial revolution. High-quality, low cost graphene devices are an integral part of making this a reality, and our latest work is a truly significant advance that could unlock graphene’s true potential,’ she said.
This work was carried out in continuation of the CARECAMM project, which successfully created ‘high-performance, cost-effective, environmentally-friendly, resistive-switching type non-volatile data storage’ in the form of sp3-rich a-C and graphene-oxide (GO) films earlier this year.
As major companies including the likes of IBM, Intel, Microsoft, Google, Facebook or Amazon will increasingly be looking for storage class memory (SCM) to improve in memory access latency and bandwidth in big data processing, CARERAMM’s technology could provide an appealing solution with high read and write speeds, bit addressability and low energy consumption as carbon memory technology matures.
The CARERAMM project was completed in January 2016 and was funded under FP7 to the tune of EUR 2.6 million.