How can we scale up graphene? Graphene Flagship scientists develop new approach optimising graphene growth and transfer

A team of researchers from Graphene Flagship partner organisations the University of Cambridge, UK and RWTH Aachen University, Germany has developed a methodology for optimising simultaneously the growth and the transfer process of graphene.

This is good news for both research and industry as a major barrier currently impeding the industrialisation of graphene is that of the mechanical transfer of graphene from a growth substrate to a target one. For most applications, graphene needs to be transferred from the growth substrate (typically copper) to a final substrate where components can be built. However, current transfer approaches either lead to a substantial degradation of the crystal quality or are not compatible with high-volume manufacturing.

Moreover, while graphene has demonstrated its potential for next generation electronics ever since its discovery, the gap between the performance of “hero devices” realised in research labs and what can be reproducibly fabricated with scalable approaches remains large. This is why high-end electronic devices enabled by graphene are still nowhere to be found on the market – and why scalability is such a challenge in terms of making the most of this nanomaterial.

This new approach developed by University of Cambridge and RWTH Aachen University researchers is especially exciting given one of the areas where there has been more progress in recent years in terms of scalability is the crystal growth of graphene. In this area, chemical vapor deposition (CVD) has matured as the leading technique to grow graphene with excellent crystal quality. The technique has faced challenges as up until now, the growth and transfer of graphene have been treated as two separate processes and optimised independently. Now, however, this new high-throughput screening approach offers an alternative solution by allowing for simultaneous optimisation of both the growth and the transfer of graphene.

Indeed, the new approach has enabled the team of scientists to demonstrate a scalable pathway for the mechanical transfer of graphene islands grown by CVD. The process ensures both high yield (>95%), and high quality of the graphene domains, with electron mobilities in the range of 40000 cm2/(Vs) at room temperature – a result that might be a real breakthrough for the industrialisation of graphene.

“The most challenging aspect of the work was the wealth of data that we generated,” says Oliver Burton, researcher at University of Cambridge and co-lead author of the paper.

“We have taken thousands of data points on thousands of individual graphene islands grown on more than 100 different crystal orientations and performed measurements throughout the entire growth and transfer process. The methodology that we have developed to weave all this information together in a meaningful way is one of the most important results of this work.

“Not only was it the key to finding a way to transfer CVD graphene with high yield and high quality, but it is also readily adaptable to a wealth of other materials systems.”

Zachary Winter, researcher at RWTH Aachen University and co-lead author of the paper, says this work is a prime example of collaboration within the Graphene Flagship.

“Within the Graphene Flagship, we could use both of our universities’ strengths – Cambridge on material growth and RWTH on device fabrication and characterisation – to analyse holistically the parameter space of the whole growth and transfer process,” says Winter.

“The high-throughput screening approach that we have developed can be the framework for optimising the growth and transfer of other 2D materials. The next objective is to realise heterostructures all based on CVD-grown materials.” 

ACS Nano 2023, 17, 2, 1229–1238
https://doi.org/10.1021/acsnano.2c09253