▎ 摘　　要

We have fabricated a planar cold cathode based on a multilayer (ML)-graphene/SiO2/Si heterostructure. When voltage is applied between the ML graphene and Si layer, electrons tunnel from the Si layer to the ML-graphene through the SiO2. During this tunneling event, electrons repeatedly gain and lose energy in the SiO2 owing to the electric field and scattering, respectively. Electrons whose energy is larger than the work function of the ML-graphene are emitted from its surface to a vacuum. The thinness of the ML-graphene reduces the energy loss of electrons in it and thus improves electron emission characteristics. (C) 2016 The Japan Society of Applied Physics