Jun 9, 2014
Manually manipulating graphene using pasters
The "wonder material" graphene is a two-dimensional material with many applications. For these, the ability to transfer high-quality graphene to various substrates without causing critical defects is required. Many methods have been developed, such as the mechanical exfoliation method and the wet chemical method, yet a quicker and easier technique is needed. Reporting in Nanotechnology, researchers have developed an improved transfer process using graphene pasters that protects the integrity of monolayer graphene.
A research team from Peking University in China has developed an approach to make manually operated monolayer graphene pasters with polyvinyl butyral (PVB). A graphene paster is a two-layer structure comprising a graphene layer and a PVB layer about 500 nm thick. The mechanical strength of the PVB layer means that the pasters have good self-supporting properties. As a result, manual manipulations to the monolayer graphene, such as clamping, moving, cutting, pasting and transfer can be easily realized. This minimizes further challenges in its subsequent applications.
Improving the transfer process
Graphene pasters can also be quickly diverted onto any substrate with sufficient contact. This overcomes some of the obstacles in graphene transfer, measurement and other applications. Through dissolving PVB with alcohol, high-quality graphene can be acquired. This improved transfer process via graphene pasters protects the integrity of monolayer graphene and makes it more applicable as it introduces few cracks or tears into the graphene.
Large-scale monolayer graphene films diverted by graphene pasters maintain low resistivity and a low Dirac point, while also exhibiting high magnetoresistance. Obvious negative magnetoresistance at low magnetic fields due to weak localization can also be observed. Graphene pasters can be used in many domains, such as field effect transistor (FET) devices, optical devices, magnetic devices and graphene superconducting quantum interference devices (SQUIDs).
More information can be found in the journal Nanotechnology 25 275704.
About the author
Yuke Wei is a graduate at the State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, Peking University in China. With a background in materials physics, his current research interests focus on graphene, and integrated systems of graphene and superconductors.