▎ 摘　　要

Cu nanoparticles (Cu NPs) were decorated on the surface of graphene films to form composite emitters. The graphene films were deposited by electrophoretic deposition and subsequently coated with Cu NPs via electrochemical reduction. The Cu NPs decorated graphene films exhibited lower turn-on field, lower threshold field and larger field enhancement factor compared with those of the pristine films. The Cu NPs decorated graphene films also showed good emission stability. The field emission properties of Cu NPs decorated graphene films were tunable through adjusting decoration time. This graphene-based composite could be used as a possible candidate for vacuum electron source. (C) 2016 Elsevier B.V. All rights reserved.