▎ 摘　　要

NOVELTY - Forming a metal nanoparticle-graphene composite involves providing a functionalized hydrogen exfoliated wrinkled graphene (f-HEG) substrate (108); and dispersing metal nanoparticles (110) on a first major surface (112) of the f-HEG substrate to form metal nanoparticle-graphene composite (114). USE - For forming a metal nanoparticle-graphene composite for field emission device (claimed); as cathode materials in a variety of electronic application e.g. flat panel displays, X-ray sources and field emission electron microscopes. ADVANTAGE - The metal nanoparticles dispersed on the functionalized hydrogen exfoliated wrinkled graphene (f-HEG) substrate reduces the work function of the substrate and substantially increases the surface roughness of the substrate, thus enhancing the field emission properties of the metal nanoparticle-graphene composite. The device has a turn-on field of 0.88 V mu m-1. The residual hydrogen atoms facilitate reduction in turn-on field and threshold field of the HEG. The charge accumulation at the edges of the substrate and at the folding of graphene provides a low-energy barrier and enhanced electron emission. Moreover, field emission devices using such composites have good stability and repeatability. The low threshold field and good field enhancement factor value compared to planar graphene can be achieved by the wrinkled morphology of HEG and the presence of residual hydrogen atoms. The turn-on field and threshold field can be reduced with metal nanoparticles dispersed on the HEG substrate. Moreover, the graphene-based composites are cost effective compared to other carbon nanostructures. Since, the maximum current density obtained for the zinc oxide (ZnO)-HEG composite is also higher than most of the field emitters and the proposed field emitter have wide area of application in the electronic industry. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a metal nanoparticle-graphene composite comprising a functionalized hydrogen exfoliated wrinkled graphene (f-HEG) substrate, and several metal nanoparticles dispersed on a first major surface of f-HEG substrate; and (2) a field emission device comprising several zinc oxide (ZnO) nanoparticles uniformly dispersed on a functionalized hydrogen exfoliated wrinkled graphene (f-HEG) substrate. DESCRIPTION OF DRAWING(S) - The figure shows materials and/or compositions used/formed at different stages of forming a metal nanoparticle-graphene composite. Materials and/or compositions (100) Graphite (102) Graphite oxide (104) Hydrogen exfoliated wrinkled graphene (106) Functionalized hydrogen exfoliated wrinkled graphene (f-HEG) substrate (108) Metal nanoparticles (110) First major surface (112) Metal nanoparticle-graphene composite (114)