Graphene-based bimorph microactuators.

A novel graphene-on-organic film fabrication method that is compatible with a batch microfabrication process was developed and used for electromechanically driven microactuators. A very thin layer of graphene sheets was monolithically integrated and the unique material characteristics of graphene including negative thermal expansion and high electrical conductivity were exploited to produce a bimorph actuation. A large displacement with rapid response was observed while maintaining the low power consumption. This enabled the successful demonstration of transparent graphene-based organic microactuators.

Wafer-scale synthesis and transfer of graphene films.

We developed means to produce wafer scale, high-quality graphene films as large as 3 in. wafer size on Ni and Cu films under ambient pressure and transfer them onto arbitrary substrates through instantaneous etching of metal layers. We also demonstrated the applications of the large-area graphene films for the batch fabrication of field-effect transistor (FET) arrays and stretchable strain gauges showing extraordinary performances. Transistors showed the hole and electron mobilities of the device of 1100 +/- 70 and 550 +/- 50 cm(2)/(V s) at drain bias of -0.75 V, respectively. The piezo-resistance gauge factor of strain sensor was approximately 6.1. These methods represent a significant step toward the realization of graphene devices in wafer scale as well as application in optoelectronics, flexible and stretchable electronics.