Dry transfer of graphene to dielectrics and flexible substrates using polyimide as a transparent and stable intermediate layer

Abstract

We demonstrate the direct transfer of graphene from Cu foil to glass and flexible substrates such as PET, using polyimide (PI) mixed with an aminosilane (3-aminopropyltrimethoxysilane) or only PI, respectively, as intermediate layer. We probe the scalability and roll-to-roll processing of this technique by using two different equipment: hot press and a laminator. High quality, clean and continuous areas of graphene monolayer can be transferred with the advantage of Cu recycling for future growth catalyst as it is peeled-off mechanically from the substrate/PI/graphene structure. More important are the high transparency of the samples together with the electron doping achieved (n<sub>S</sub>= 0.21 to 4 x 10<sup>13</sup> cm<sup>-2</sup>), as the performing graphene face is not in direct contact with PMMA, PI or other materials, and the high mobility (µ<sub>H</sub> up to 1250 cm<sup>2</sup>/Vcenterdots). Stability of the structure in terms of sheet resistance (R<sub>S</sub>) at high temperatures, bending cycles and water immersion make this technique promising for future applications and implementation at the large scale.