Enhanced photolithography with Al film insertion for large-scale patterning of CVD graphene

Abstract

In this paper, enhanced photolithography with Al film insertion for large-scale patterning of chemical-vapor-deposited graphene is proposed and demonstrated. An Al film was evaporated onto the surface of graphene, and then traditional photolithography and wet etching were used to make an Al mask. After Ar plasma treatment and removal of the Al mask, patterned graphene was obtained on the target substrate. Graphene patterns fabricated by conventional photolithography were utilized as reference samples. Compared to conventional patterned graphene, the graphene patterns exhibited obviously less residual photoresist (PR), high resolution, and can be applied to various shapes and sizes. It is worth mentioning that the pitch can reach the limit of photomasking utilized in this study. In addition, the graphene also shows a relatively lower work function (~4.2 eV), better photoelectric properties (sheet resistance ~531 Ω/sq, T550 = 94.2%), and outstanding surface hydrophilicity (water contact angle 49°). It is anticipated that graphene patterns realized by the proposed approach could make the application of graphene more promising in emerging and future optoelectronic devices.