Method for preparing graphene-carbon nano-tube pure carbon composite membrane

The invention discloses a method for preparing a graphene-carbon nano-tube pure carbon composite membrane. The method comprises the following steps: (1) preparing a graphene membrane by using a copper foil as a substrate by a normal pressure CVD method, adding carbon nano-tube powder into o-dichlorobenzene, and performing ultrasonic treatment in an ultrasonic cleaning machine to obtain a uniform and stable carbon nano-tube dispersion liquid; (2) uniformly dispersing the carbon nano-tube dispersion liquid onto the graphene membrane by means of titration film coating, and removing solvent by thermal treatment to obtain a copper foil-graphene-carbon nano-tube material; (3) performing ion beam irradiation treatment on the copper foil-graphene-carbon nano-tube material; and (4) etching the treated copper foil-graphene-carbon nano-tube material to remove the copper foil, picking out the composite membrane floating on the etching liquid, and washing in deionized water to remove residual etching liquid so as to obtain the pure carbon composite membrane. The membrane has good light transmission and good conductivity, can be used as a novel pure carbon composite material, and has a wide potential application value in field effect transistors, laser mode locking and other fields.