▎ 摘　　要

NOVELTY - A gamma -ray is irradiated to a graphene oxide solution and reduced, to obtain graphene. USE - Manufacture of graphene used for manufacturing metal nanoparticles, thin conductive film, transparent electrode, memory device, solar cell, organic light-emitting device, electric component, and biodevice e.g. biosensor, biochip and neuron on-chip (all claimed). ADVANTAGE - The method enables economical manufacture of graphene having excellent conductivity with high yield and reduced energy consumption, without environmental pollution.