Korean researchers fabricated a stretchable, transparent graphene-based transistor. They say that the new to transistor overcomes some of the problems faced by transistors made of conventional semiconductor materials - which simply cannot be made stretchable and transparent on substrates such as rubber slabs or balloons.
To make the transistor, the researchers synthesized single layers of graphene and then stacked them layer by layer on copper foil. Using photolithography and etching techniques, the researchers patterned some of the transistor’s essential elements, including the electrodes and semiconducting channel, onto the graphene. After transferring these components onto a stretchable rubber substrate, the researchers printed the remaining components – gate insulators and gate electrodes – onto the device using stretchable ion gel.
The graphene based transistors could be stretched up to 5% for 1,000 times and still maintain their good electrical properties. In one experiment, the researchers fabricated the graphene transistors on a rubber balloon and measured its electrical properties as they inflated the balloon. When stretched more than 5%, the electrical properties began to degrade, due partly to microcracks and other defects in the graphene films.